Table Of Contents
Link Bundling on Cisco 12000 Series Internet Routers
Using EtherChannel Link Bundles
Using POS Channel Link Bundles
Link Bundling in a Cisco 12000 Series Internet Router
Load-balancing in Cisco 12000 Series Link Bundles
Software Features Supported on a Link Bundle
Using an EtherChannel for High-Speed Provider Edge Support
Any Transport over MPLS—Ethernet over MPLS
Stacked VLAN Processing—802.1Q-in-Q
Feature Parity on VLAN and Stacked VLAN Member Interfaces
Unicast Reverse Path Forwarding
Feature Parity on POS Channel Bundles
Route Processor Redundancy Plus
Restrictions for Link Bundling
Related Features and Technologies
Supported Standards, MIBs, and RFCs
Configuring a Port-Channel Interface
Configuring a POS-Channel Interface
Adding a Fast Ethernet or Gigabit Ethernet Interface
Adding a Packet-over-SONET Interface
Maximizing VLAN TCAM to Support VLAN Scalability
Removing an Ethernet or Packet-over-SONET Interface from a Link Bundle
Configuring Out-of-Service Support
Configuring Bandwidth Propagation
Configuring a VLAN EtherChannel
Configuring Out-of-Service Support
Configuring Bandwidth Propagation
hw-module slot linkbundle-tcam-scalability
Link Bundling on Cisco 12000 Series Internet Routers
Part Number OL-8696-01, May 30, 2008
Feature History
12.0(23)S
This feature was introduced on Engine 0, Engine1, and Engine 2 line cards on the Cisco 12000 series Internet router.
12.0(26)S
This feature was introduced on IP Service Engine (ISE/E3) and Engine 4 Plus (E4+) line cards on the Cisco 12000 series Internet router.
The following new features were introduced:
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Out-of-service support
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12.0(32)S
Support was added for the following features in a link bundle that consists only of ISE/E3 or E4+ Gigabit Ethernet (GE) member interfaces in a
Cisco 12000 series Internet router deployed on the provider edge:•
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Engine 5 Ingress support was added.
VLAN ID-based mode of load-balancing was added.
route processor redundancy plus (RPR+) support in link bundles was added.12.0(33)S
Support was added for the following features in an ISE/E3 link bundle that consists of POS or GE member interfaces:
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Support was added for Engine 5 (E5) Fast Ethernet member interfaces in an EtherChannel link bundle.
Engine 5 Egress support was added so that the following features are now supported in an EtherChannel link bundle that consists of E5 Fast Ethernet or Gigabit Ethernet member interfaces:
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Cisco IOS software feature parity between a POS channel that consists of ISE, E4+, E5, or E6 member interfaces and EtherChannel bundles was added. Table 4 lists supported features.
Stateful Switchover (SSO) support in link bundles was added.
This feature module describes how to configure and use the Link Bundling feature on Cisco 12000 series Internet routers. This document includes the following sections:
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Feature Overview
The Link Bundling feature allows you to group multiple point-to-point links together into one logical link to provide higher bidirectional bandwidth (a bigger pipe), redundancy, and load-balancing between two routers. The following types of link bundling are supported on Cisco 12000 series Internet routers:
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Managing Bandwidth
All three link bundling methods on Cisco 12000 series Internet routers provide flexible and incremental bandwidth with link redundancy and greater layer transparency to network applications. You can use link bundles in multiple locations in the same network.
Use link bundling on Cisco 12000 series Internet routers in networks under the following conditions:
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EtherChannels and POS channels allow you to increase and decrease bandwidth by adding or removing an interface from the link bundle. Also, by incrementally increasing bandwidth, you are no longer dependent on the fixed increases in bandwidth (for example, 1 Gbps, 10 Gbps, and so on) determined by the physical layer technology.
Managing Link Failure
The failure of one link does not necessarily cause a network failure. Traffic is redirected to remaining links within the channel without user intervention. As a result, the availability of a FE, GE, or POS link is increased.
On Cisco 12000 series Internet routers, link bundling is implemented so that a virtual interface is created for each link bundle. You can dynamically add and delete links to the virtual interface. The virtual interface is treated as one interface on which you configure an IP address and other software features used by the link bundle, instead of configuring them on individual GE and POS interfaces.
Packets sent to the link bundle are forwarded on one of the links in the bundle. Load-balancing is supported on all links in a bundle using per-destination load-balancing based on a hash calculated using the source and destination IP addresses in the IP packet. Per-destination load-balancing ensures that packets are delivered in order.
For a description of how to use EtherChannel and POS channel link bundling on Cisco 12000 series Internet routers, see the "Using EtherChannel Link Bundles" section and the "Using POS Channel Link Bundles" section.
Link Bundling Features
Beginning in Cisco IOS Release 12.0(26)S, support for the following features is added to link bundling on Cisco 12000 series Internet routers:
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For a description of how to configure out-of-service support and bandwidth propagation, see the "Configuring Out-of-Service Support" section and the "Configuring Bandwidth Propagation" section.
Using EtherChannel Link Bundles
EtherChannel link bundles are at Layer 2 and use one MAC address and one IP address for all FE or GE interfaces in the bundle. A Fast or Gigabit EtherChannel is used mostly in intra-POP applications to interconnect multiple routers. Figure 1 shows how to aggregate Gigabit Ethernet links into one Gigabit EtherChannel interface in an intra-POP application.
Figure 1 Gigabit EtherChannel Used in an Intra-POP Application
You can also use an EtherChannel in metropolitan area networks for Ethernet aggregation at the network edge. For example, you can use a Gigabit EtherChannel to connect multiple sites that are moving from using 1 Gbps to 10 Gbps throughput. Bandwidth demand grows at different rates in metropolitan network sites, depending on business needs and data traffic patterns. You can, therefore, use Gigabit EtherChannel to incrementally increase bandwidth in 1-Gbps segments.
Using POS Channel Link Bundles
POS channel link bundles are at Layer 2 and use one logical IP interface. You can use POS channel link bundling in intra-POP applications (Figure 2), and in backbone (Figure 3) and peering connections.
For example, if the fiber infrastructure required to support greater transmission speeds does not exist, bundling together multiple POS connections is useful. A POS channel link bundle provides an alternative way to support OC-48, OC-192, or OC-768 transmission speeds.
Figure 2 POS Channel Used in an Intra-POP Application
Figure 3 POS Channel Used in a Backbone Application
Link Bundling in a Cisco 12000 Series Internet Router
Link bundling is a capability that must be supported on a system-wide level in a Cisco 12000 series Internet router. The Link Bundling feature requires that each line card in the router recognize an EtherChannel or POS channel bundle as a virtual interface.
The successful flow of data packets into and out of a link bundle consists of the following steps:
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If the ingress line card:
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Engine 5 Ingress Support
Starting in Cisco IOS Release 12.0(32)S, EtherChannel bundles support load-balancing across member links for the following combinations of IP and MPLS data streams when an Engine 5 line card is the ingress interface and an EtherChannel port-channel interface is the egress interface in a Cisco 12000 series Internet router. An Engine 5 ingress interface:
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In these conditions, IP and MPLS packets are load-balanced across the member links in an EtherChannel bundle. For more information about MPLS tag switching, refer to MPLS/Tag Switching.
Load-balancing in Cisco 12000 Series Link Bundles
On Cisco 12000 series Internet routers, EtherChannel, and POS channel link bundling provides load-balancing (equal cost) across all active links in the bundle. Load-balancing (also known as Layer 2 load-balancing) is supported on the links using per-destination load-balancing, based on a hash calculated using the source and destination IP addresses in the IP packet. Per-destination load-balancing ensures that packets are delivered in order.
In an EtherChannel or POS channel link bundle, you can only configure interfaces of the same engine and media type. (For more information, see "Line Card Restrictions in Routers on Each Side of a Link Bundle" section.) Each engine type uses a different hash algorithm to perform load-balancing across member interfaces in a link bundle.
Load-balancing logic is built into the CPU software of lower engine types and into the Layer 3 packet-switching ASIC (PSA) driver modules of higher engine types. Load-balancing logic is stored:
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Equal load-balancing across all links in a bundle occurs only when the source and destination IP addresses in packets vary across a wide range of IP addresses.Starting in Cisco IOS Release 12.0(32)S, VLAN ID-based load-balancing, is supported. See "VLAN ID-Based Load-balancing" section for more information.
VLAN ID-Based Load-balancing
VLAN ID-based load-balancing is supported on the port-channel interface of an EtherChannel bundle that consists of the following member interfaces:
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Outgoing traffic is normally equally balanced across all links in a bundle based on the source and destination IP address of transmitted packets. However, VLAN ID-based load-balancing in a link bundle introduces load-balancing based on the VLAN ID of transmitted packets.
When you configure VLAN ID-based load-balancing, all egress traffic with a specified VLAN ID is internally mapped to outgoing member interfaces through which the traffic is transmitted. To switch between VLAN ID-based and per-destination load-balancing, use the channel-group load-share vlan command in (port-channel) interface configuration mode.
Use VLAN ID-based load sharing in a link bundle in the following configurations:
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The VLAN ID-to-interface mapping is performed by assigning the traffic for each VLAN ID according to the load supported on a member interface and the load required by the VLAN. The load required for VLAN traffic is calculated as the bandwidth allocated to the Modified Deficit Round Robin (MDRR) queue. New VLAN traffic is assigned to the member interface transmitting the smallest load. The total load of egress VLAN traffic in a link bundle is balanced among member interfaces. If a change in the number of active member links available for use occurs, the VLAN ID-to-interface mapping is recalculated.
Software Features Supported on a Link Bundle
Sometimes the software features supported on an Fast Ethernet, Gigabit Ethernet, or POS interface are not supported on the entire link bundle because of engineering restrictions. For example, IPv6 is not supported on a link bundle. Configuring an unsupported feature on an EtherChannel or POS channel link-bundle interface may result in unexpected behavior.
On Cisco 12000 series Engine 0 (E0), E1, and E2 line cards, the minimum set of software features supported across an entire link bundle (port-channel or pos-channel and member interfaces) is:
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On Cisco 12000 series ISE/E3, E4+, and E5 line cards, the minimum set of software features supported on the port-channel or pos-channel and member interfaces is:
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Equal-cost load-balancing of IP traffic is performed across all active links in a link bundle.
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An EtherChannel interface supports the configuration of VLAN subinterfaces. However, the configuration of stacked (802.1Q-in-Q) processing is only supported on certain EtherChannel interfaces. For more detailed information, see "Stacked VLAN Processing—802.1Q-in-Q" section.
For an example of how to configure an EtherChannel that consists of Ethernet VLAN links, see the "Configuring a VLAN EtherChannel" section.
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Equal-cost load-balancing of MPLS traffic is performed across all active links in a link bundle.
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A Layer 3 MPLS VPN configuration is supported on an EtherChannel or POS channel interface that is used in any of the following Provider Edge (PE) router configurations:
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Using an EtherChannel for High-Speed Provider Edge Support
In addition to the minimum set of software features described in the "Software Features Supported on a Link Bundle" section, the following software features are also supported in an EtherChannel that consists of ISE (E3), Engine 4+ (E4+), or Engine 5 (E5) member interfaces in a Cisco 12000 series Internet router that is deployed as a provider edge (PE) router:
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Any Transport over MPLS—Ethernet over MPLS
The following Any Transport over Multiprotocol Label Switching (AToM)—Ethernet over MPLS (EoMPLS) features are supported only on the port-channel (logical) interface of an EtherChannel bundle that is configured for EoMPLS:
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EoMPLS provides the following benefits:
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For more information about how to configure and use EoMPLS, refer to Any Transport over MPLS.
Ethernet over MPLS—VLAN Mode
In an MPLS network, the Ethernet over MPLS (EoMPLS) feature enables you to connect two VLAN networks located in different locations, without using bridges, routers, or switches at the VLAN locations. You can enable the MPLS backbone network to accept Layer 2 VLAN traffic by configuring the label edge routers (LERs) at both ends of the MPLS backbone.
In the Link Bundling feature on the Cisco 12000 series Internet router, EoMPLS is supported on the port-channel interface of an EtherChannel bundle that consists of the following member interfaces and only in VLAN mode:
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You can configure an EtherChannel with EoMPLS on the ingress interface of a PE router in a PE-CE (customer edge) connection or on the egress interface in a PE-P provider-core router connection.
VLAN mode transports Ethernet traffic from a source 802.1Q VLAN to a destination 802.1Q VLAN (including stacked VLAN 802.1Q-in-Q traffic) over a core MPLS network. You must configure Ethernet over MPLS (VLAN mode) on the subinterfaces of member interfaces.
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When you configure EoMPLS on a port-channel interface, AToM virtual circuits (VCs) are transparently distributed on the interfaces of the member links in PE-to-P router connections by the AToM control plane, which views the link bundle as one virtual interface. A VC label is allocated on a per-VLAN basis. Because all Ethernet packets are forwarded on the same path for a given VLAN, the egress VLAN ID is used to obtain the Layer 2 adjacency.
On the port-channel interface, EoMPLS also supports the VLAN ID Rewrite feature, which enables you to use VLAN interfaces with different VLAN IDs at both ends of the tunnel.
In an EoMPLS configuration on a port-channel interface, only VLAN ID-based load-balancing is supported.
Layer 2 Quality of Service
On the Cisco 12000 series Internet router, Layer 2 QoS features that are normally supported on Fast or Gigabit Ethernet interfaces (see the "Quality of Service" section) are supported on the port-channel (Layer 3) interface of a link bundle that is configured for EoMPLS and consists of the following member interfaces:
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Supported Layer 2 QoS features include:
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Policing and shaping Layer 2 VPN traffic at the MPLS imposition and disposition interfaces allows a service provider to offer service level agreements (SLAs) to customers in terms that include bandwidth, delay, jitter, and packet-loss guarantees in an EtherChannel connection. At imposition, Ethernet QoS markers are mapped to MPLS experimental bits. The traffic can be classified by the MPLS experimental bit then policed and shaped on provider interfaces.
For traffic traversing an EtherChannel, Modified Deficit Round Robin (MDRR) Congestion management and Weighted Random Early Detection (WRED) congestion avoidance are supported for MPLS packets with Layer 2 VPN payloads. Because packet queuing characteristics vary among Cisco 12000 series line cards, MDRR and WRED configurations can vary with the line card combinations used for MPLS imposition and disposition interfaces.
The following restrictions apply to Layer 2 QoS features configured on a port-channel interface:
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For a complete description and configuration information of the Layer 2 QoS features supported on Cisco 12000 series ISE and E5 interfaces, refer to Any Transport over MPLS (AToM): Layer 2 QoS (Quality of Service).
Layer 2 Local Switching
The Layer 2 Local Switching feature allows you to switch Layer 2 data between two interfaces of the same type (for example, Ethernet to Ethernet VLAN) or between interfaces of different types (for example, ATM to Ethernet) on the same router.
In the Link Bundling feature on the Cisco 12000 series Internet router, Layer 2 Local Switching is supported on the port-channel interface of an EtherChannel bundle that is configured for EoMPLS and consists of the following member interfaces:
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In addition, Layer 2 local switching is only supported for "like-to-like" switching between two member interfaces or subinterfaces of the same type as follows:
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Apart from "like-to-like" switching, ATM-Ethernet interworking mode (bridged mode) for link bundling is also supported.
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The interfaces can reside on the same line card or on two different cards. During these kinds of like-to-like switching, the Layer 2 address is used, not any Layer 3 address. Additionally, same-port local switching allows you to switch Layer 2 data between two circuits on the same interface. For more information, refer to Layer 2 Local Switching.
In an EtherChannel, local switching involves switching Ethernet packets between customer edge (CE) routers that are on the same side of the connection as the Cisco 12000 series Internet (PE) router. Because the packet switching is performed using fake VC labels in a way similar to AToM label imposition, the VC label cannot be used for load-balancing. For load-balancing, the hash index is calculated using the VLAN ID in EoMPLS VLAN mode. (EoMPLS port mode is not supported for Layer 2 local switching.) The hash index is used to select the adjacency and is programmed into the hardware.
Layer 2 Protocol Tunneling and PDU Filtering
In the Link Bundling feature on the Cisco 12000 series Internet router, EoMPLS supports Layer 2 protocol tunneling (L2PT) and Layer 2 PDU filtering on the port-channel interface of an EtherChannel bundle that consists of the following member interfaces:
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Layer 2 protocol tunneling allows service providers to carry traffic from multiple customers across a core network, and maintain the VLAN and Layer 2 protocol configurations of each customer without impacting the traffic of other customers. The Transparent Layer 2 Protocol Tunneling feature allows Layer 2 protocol data units (PDUs) to be tunneled across the core network without being interpreted and processed by intermediary network devices. Layer 2 PDU filtering allows a service provider to specify which Layer 2 PDUs are to be dropped at an ingress interface on a provider edge (PE) router. Transparent Layer 2 Protocol Tunneling and PDU filtering provide an enhanced feature set for service providers that transmit customer VLAN traffic from metro Ethernet VPNs across an MPLS core network.
Transparent Layer 2 protocol tunneling and PDU filtering are intended for use on provider edge (PE) routers in an MPLS-enabled service-provider core network.
For more information, refer to Transparent Layer 2 Protocol Tunneling and PDU Filtering.
Stacked VLAN Processing—802.1Q-in-Q
Stacked VLAN processing is supported only on the port-channel interface of an EtherChannel bundle that consists of the following member interfaces:
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The Stacked VLAN Processing feature supports the encapsulation of IEEE 802.1Q VLAN tags within a second layer of 802.1Q tag on provider edge (PE) routers to allow service providers to use a single VLAN to support customers who have multiple VLANs. The core service-provider network carries traffic with double-tagged, stacked VLAN (802.1Q-in-Q) headers of multiple customers while maintaining the VLAN and Layer 2 protocol configurations of each customer and without impacting the traffic of other customers. The Stacked VLAN Processing feature preserves VLAN IDs and keeps traffic in different customer VLANs segregated.
To allow a subinterface in an EtherChannel bundle on a PE-POP Cisco 12000 series Internet router to connect to a third-party PE-CLE switch that supports an EtherType value that is different from the default Cisco EtherType value (0x8100), enter the dot1q tunneling ethertype command on the port-channel interface. (The EtherType value supported on Cisco routers and switches is 0x8100. The networking devices of some other vendors support EtherType 0x9100.)
After you enter this command, only stacked VLAN packets with the specified EtherType value in the SP-VLAN tag of the packet header are received on subinterfaces in the link bundle. The new EtherType value is used in the SP-VLAN tag of all stacked VLAN packets sent from subinterfaces in the EtherChannel bundle to the PE-CLE switch, except if EoMPLS is configured on the port-channel interface. If EoMPLS is configured, all traffic received on an EoMPLS member interface (or subinterface) is sent to the PE-CLE switch as it was received from the peer PE router, without the new EtherType value.
For more information about how to configure and use stacked VLAN processing, refer to Stacked VLAN Processing.
Feature Parity on VLAN and Stacked VLAN Member Interfaces
VLAN and Stacked VLAN subinterfaces on member interfaces support all software features that are supported on a port-channel interface of an EtherChannel bundle that consists of the following member interfaces:
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Some of the software features supported both on the EtherChannel interface and member VLAN and stacked VLAN subinterfaces include:
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MAC Address Accounting
MAC address accounting is supported only on the port-channel interface of an EtherChannel bundle that consists of the following member interfaces:
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The MAC address accounting feature provides accounting information for IP traffic based on the source and destination MAC addresses on LAN interfaces. This feature calculates the total packet and byte counts for the EtherChannel that receives or sends IP packets to or from a unique MAC address. It also records a timestamp for the last packet received or sent.
To configure a port-channel interface for IP accounting based on the MAC address, enter the ip accounting mac-address {input | output} command in interface configuration mode, where:
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To display the MAC accounting information for an EtherChannel, use the show interfaces mac command in privileged EXEC mode.
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Multicast and Multicast VPN
Multicast routing protocols and multicast VPN are supported on the 802.1Q VLAN and stacked VLAN 802.1Q-in-Q subinterfaces and on the port-channel interface of an EtherChannel bundle that consists of the following member interfaces:
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Multicast Routing Protocols
You can enable multicast routing protocols on the port-channel interface and 802.1Q VLAN and 802.1Q-in-Q subinterfaces of an EtherChannel bundle, including Internet Group Management Protocol (IGMP), Protocol-Independent Multicast (PIM), Protocol Independent Multicast dense mode (PIM-DM), PIM sparse mode (PIM-SM), source specific multicast (SSM), Multicast Distributed Switching (MDS), Distance Vector Multicast Routing Protocol (DVMRP), and Cisco Group Management Protocol (CGMP).
For information about how to use and configure multicast routing protocols, refer to:
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Multicast Fast-path Forwarding
Multicast fast-path forwarding allows hardware-based fast forwarding of IPv4 multicast traffic, resulting in high throughputs and performance. Packet forwarding is performed in the hardware switching engine instead of on the line card CPU. For more information, refer to Fast-Path Multicast Forwarding on Cisco 12000 Series Engine 2 and ISE Line Cards.
Multicast VPN
Multicast VPN provides the ability to support the multicast feature over a Layer 3 VPN. A multicast VPN allows an enterprise to transparently interconnect its private network across the network backbone of a service provider. Because MPLS VPNs support only unicast traffic connectivity, deploying the Multicast VPN feature in conjunction with MPLS VPN allows service providers to offer both unicast and multicast connectivity to MPLS VPN customers.
The Multicast VPN—IP Multicast Support for MPLS VPNs feature allows a service provider to configure and support multicast traffic in an MPLS Virtual Private Network (VPN) environment. This feature supports routing and forwarding of multicast packets for each individual VPN routing and forwarding (VRF) instance, and it also provides a mechanism to transport VPN multicast packets across the service provider backbone. For more information about this feature, refer to Multicast VPN—IP Multicast Support for MPLS VPNs.
Multicast QoS
Quality-of-service (QoS) features, which are supported on Fast Ethernet or Gigabit member interfaces and VLAN subinterfaces, are also supported in the egress direction on an EtherChannel interface configured for multicast traffic. For more information about this feature, refer to Multicast Egress QoS Support on Cisco 12000 Series Router, Integrated Services Engine (ISE) Line Cards. For more information on specific QoS features and the EtherChannels on which they are supported, see the "Quality of Service" section.
Multicast Configuration Commands
You must configure all multicast and multicast VPN commands on the port-channel interface associated with an EtherChannel after you enter the interface port-channel command. The configuration of multicast commands is not supported on:
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The multicast and multicast VPN control plane and protocols that you configure on a port-channel interface are not aware of the member interfaces. All packets transmitted through member interfaces appear to the multicast control plane as packets sent through the logical EtherChannel interface. All multicast show commands that you enter on the control-plane level display multicast information for the port-channel (logical) interface.
Load-balancing for multicast traffic is performed using a hash algorithm that takes group information in (*,G) entries and (S,G) entries. The outgoing member link is selected using the source and destination IP addresses. If you enable VLAN ID-based load-balancing, multicast traffic is forwarded based on the VLAN ID of transmitted packets.
Policy-Based Routing
Policy-based routing (PBR) is supported on the port-channel interface of an EtherChannel bundle that consists of the following member interfaces:
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You can also configure a routing policy for individual Fast Ethernet and Gigabit Ethernet member subinterfaces.
Policy-based routing provides a flexible means of routing packets by allowing you to configure a defined policy for traffic flows, lessening reliance on routes derived from routing protocols. You can set up PBR as a way to route packets based on configured policies. For example, you can implement routing policies to allow or deny paths based on the identity of a particular end system or an application protocol.
You can configure a unique routing policy for any of the following:
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A policy contains one or more route maps. Each route map has one or more statements that specify the required matching criteria and actions. For example, a matching statement can be an access control list (ACL). If the matching criteria are met, the action statements are executed. An action statement can contain a routing action or a quality of service (QoS) action. The routing action determines the output interfaces for a packet or the next hop. The QoS action may be to set the type of service (ToS) or IP precedence parameter to a specific value.
For information about configuring policy-based routing, refer to Configuring Policy-Based Routing.
Unicast Reverse Path Forwarding
The Unicast Reverse Path Forwarding (Unicast RPF) feature is supported in an EtherChannel bundle as follows:
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The Unicast Reverse Path Forwarding Loose Mode feature provides a scalable anti-spoofing mechanism for use in multihome network configuration. This mechanism is effective in service-provider networks on routers that have multiple links to multiple Internet service providers (ISPs), on an ISP-to-ISP network edge.
Unicast RPF (loose or strict mode) provides a quick reaction mechanism for dropping network traffic on the basis of either the source or destination IP address. Network administrators can use this configuration as a tool for mitigating denial of service (DoS) and distributed denial of service (DDoS) attacks.
Verifying Source IPv4 Addresses
The difference between loose and strict checking modes is as follows:
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To provide ISPs with a DDoS resistance tool on the ISP-to-ISP edge of a network, Unicast RPF is enhanced from its original strict mode implementation to check the source addresses of each ingress packet without regard for the specific interface on which it was received.
You can enable Unicast RPF in strict or loose mode on an EtherChannel interface or subinterface. For information about enabling Unicast RPF, refer to Unicast Reverse Path Forwarding Loose Mode or Unicast Reverse Path Forwarding in Strict Mode on the Cisco 12000 Series Internet Router.
VLAN Scalability
Enhanced VLAN scalability is only supported on the port-channel interface of an EtherChannel bundle that consists of the following member interfaces:
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In Cisco IOS Release 12.0(31)S and earlier releases, when you create a subinterface on a member interface of an EtherChannel bundle, a subinterface is also created on all other member interfaces in the bundle. The following equation shows the total number of software data structures (known as IDBs) used for tracking Cisco IOS interfaces and interface status when you configure N number of subinterfaces in a link bundle:
Number of IDBs created = (1 + M) x N
Where:
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For example, if a link bundle consists of 4 member interfaces and you configure 2 subinterfaces on member interfaces, the total number of IDBs created is 10.
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The equation shows how the number of subinterfaces supported on an EtherChannel bundle, and therefore the number of supported VLANs, is limited due to the increased amount of route processor memory used by the IDBs.
For this reason, in Cisco IOS Release 12.0(31)S and earlier releases, the number of VLANs supported in an EtherChannel bundle that consists of 4-port Gigabit Ethernet ISE member interfaces is 300. However, starting in Cisco IOS Release 12.0(32)S and later releases, a software enhancement allows you to configure up to 1000 VLANs on the supported Gigabit Ethernet member interfaces in a link bundle. Engine 5 Fast Ethernet member interfaces are supported starting in Cisco IOS Release 12.0(33)S.
In addition, when you increase the number of VLANs on the member interfaces of an EtherChannel, the performance of VLAN load-balancing and data transmission depends on the percentage of ternary content addressable memory (TCAM) allocated for VLANs on each line card, whose interfaces belong to the link bundle. You can maximize the VLAN TCAM size allocated to each ISE/E3 Gigabit Ethernet subinterface by using the hw-module slot linkbundle-tcam-scalability command (see the "Maximizing VLAN TCAM to Support VLAN Scalability" section). When you enter this command, the Layer 2 TCAM regions on an ISE (E3) line card are recarved to support 1K of VLAN traffic on each subinterface in a link bundle.
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Quality of Service
The Quality-of-Service (QoS) features described in this section are supported only on the port-channel interface of an EtherChannel bundle that consists of the following member interfaces:
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Certain QoS features supported on Ethernet interfaces are also supported when you assign these interfaces to an EtherChannel bundle. See Table 1, Table 2, and Table 3 for a list of supported QoS features.
The following restrictions apply when you use QoS features in an EtherChannel bundle:
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To configure QoS features, you must use the modular Quality-of-Service command-line (MQC) interface. For information, refer to:
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For E3 link bundling interfaces, QoS policies are not attached on secondary RP in SSO redundancy mode after one of the following:
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After the switchover, remove and reattach QoS policies to enable them again. Also, switch to RPR or RPR+ redundancy mode toavoid secondary RP crash.
Table 1 QoS Features Supported on 4-port Gigabit Ethernet ISE Interfaces in an EtherChannel
Table 2 QoS Features Supported on Modular Gigabit Ethernet Interfaces in an EtherChannel
Committed access rate (CAR) using rate-limit
Not supported
Not supported
Modified Deficit Round Robin (MDRR)
Not supported
Not supported
Weighted Random Early Detection (WRED)
Not supported
Not supported
set cos (egress only)
Not supported
Not supported
set discard-class (ingress only)
Supported
Not supported
set dscp
Supported
Not supported
set ip precedence
Supported
Not supported
set mpls experimental
Supported
Not supported
set qos-group (ingress only)
Supported
Not supported
Shaping
Not supported
Not supported
Hierarchical shaping
Not supported
Not supported
Hierarchical policing
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Table 3 QoS Features Supported on Engine 5 Fast and Gigabit Ethernet Interfaces in an EtherChannel
Feature Parity on POS Channel Bundles
Starting in Cisco IOS Release 12.0(33)S, the same level of support for IOS software features exists on a POS channel bundle that consists of ISE, E4+, E5, and E6 member interfaces as on an EtherChannel link bundle. For a description of the supported software features, see the "Software Features Supported on a Link Bundle" section and the "Using an EtherChannel for High-Speed Provider Edge Support" section.
Table 4 summarizes the support for each Cisco IOS software feature in a POS channel link-bundle interface according to the engine type of member interfaces.
Table 4 IOS Software Features Supported on a POS Channel Interface by Engine Type
Route Processor Redundancy Plus
Both EtherChannel and POS channel bundles support the Route Processor Redundancy Plus (RPR+) feature. The standby route processor (RP) maintains an updated configuration of the link bundle for use during the switchover.
When two RPs are installed in a Cisco 12000 series Internet router chassis, one RP acts as the active RP, and the other acts as a backup (or standby) RP. If the active RP fails or is removed from the system, the standby RP detects the failure and initiates a switchover. During a switchover, the standby RP assumes control of the router, connects with the network interfaces, and activates the local network management interface and system console.
Using the RPR+ feature, the standby RP is fully initialized and configured, which allows RPR+ to dramatically shorten the switchover time if the active RP fails or if a manual switchover is performed. Because both the startup configuration and the running configuration are continually synchronized from the active to the standby RP, line cards are not reset during a switchover. The state of the interfaces does not change during switchover, so that neighboring routers do not detect a link flap (that is, the link does not go down and back up). For more information, refer to Route Processor Redundancy Plus for the Cisco 12000 Series Internet Router.
Stateful Switchover
Both EtherChannel and POS channel bundles also support the Stateful Switchover (SSO) feature. Like the RPR+ feature, SSO is one link in a chain of Cisco IOS redundancy features designed to provide progressively higher system and network availability.
In a Cisco 12000 series Internet router that support dual RPs, SSO takes advantage of RP redundancy to synchronize critical state information between the active and standby RP. Following an initial synchronization between the two processors, SSO dynamically maintains RP state information between them.
SSO mode provides all the functionality of RPR+ in that Cisco IOS software is fully initialized on the standby RP. In addition, SSO supports synchronization of line card, protocol, and application state information between RPs for supported features and protocols (a "hot standby").
A switchover from the active to the standby processor occurs when the active RP fails, is removed from the networking device, or is manually taken down for maintenance. Because SSO is used with the Cisco Nonstop Forwarding (NSF) feature, Cisco NSF allows for the forwarding of data packets to continue along known routes while the routing protocol information is being restored following a switchover. With Cisco NSF, peer networking devices do not experience routing flaps, thereby reducing loss of service outages for customers.
Unlike the RPR+ feature, the last known FIB information is used by the backup RP when it takes over the active RP function. All link bundle activity (for example, active-to-passive member transition, VLAN load-balancing, bandwidth changes) is synchronized in the standby RP. During the switchover, packet forwarding in link bundles remains uninterruptred.
For information about the differences between the RPR+ and SSO redundancy modes and how to configure SSO, refer to Stateful Switchover.
Benefits of Link Bundling
EtherChannel and POS channel link bundling on Cisco 12000 series Internet routers provide the following benefits:
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Restrictions for Link Bundling
Line Cards Supported on the Cisco 12000 Router
EtherChannel and POS channel link bundling are supported on the following line cards in Cisco 12000 series Internet routers:
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Line Card Restrictions in Routers on Each Side of a Link Bundle
In an EtherChannel or POS channel link bundle, the following restrictions apply:
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For example, stacked VLAN (802.1Q-in-Q) processing is supported in a Engine 5 Gigabit EtherChannel only if all member interfaces are on SPAs that use the Engine 5 Version 2 FUGU ASIC. The Version 1 GILA ASIC does not support stacked VLAN processing.
For information about which Engine 5 line cards support the different ASIC versions, refer to Supported Line Cards for the 12000 Series Routers in the Cross-Platform Release Notes for Cisco IOS Release 12.0S.
Symmetric Configuration on Both Sides of a Link Bundle
In both EtherChannel and POS channel link bundles, the Link Aggregation Control Protocol (LACP) for signalling and the 802.3ad protocol for automatic negotiation of the channel are not supported. This means that in order for the channel between two routers to be active, you must disable signaling on switches (such as the Cisco 6500/7600 Series) in the channel, and configure the switches in ON mode.
In addition, an EtherChannel or POS channel between two adjacent routers must be configured with the same number of members (interfaces) on the router at each end of the channel. This is required for an EtherChannel or POS channel interface to function correctly and for the link status to come up.
Ingress Decision Support
For an EtherChannel or POS channel to operate correctly with equal cost load-balancing, the Link Bundling feature requires that all line cards in a Cisco 12000 series Internet router support the ingress decision capability (described in the "Link Bundling in a Cisco 12000 Series Internet Router" section).
Only the following Cisco 12000 series line cards support ingress decision capability:
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The following Cisco 12000 series line cards do not support ingress decision capability:
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Engine 5 Ingress and Egress Support
Starting in Cisco IOS Release 12.0(32)S, Engine 5 line cards are supported as the ingress interface when an EtherChannel port-channel interface is the egress interface in a Cisco 12000 series Internet router. In this case, an EtherChannel bundle supports load-balancing for IP and MPLS packets across member links for the following combinations of IP and MPLS data streams. An Engine 5 ingress interface:
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For more information about MPLS tag switching, refer to MPLS/Tag Switching.
Starting in Cisco IOS Release 12.0(33)S, Engine 5 line cards are also supported as the egress interface on which you can configure a virtual interface (EtherChannel or POS channel) for a link bundle. For a list of supported Engine 5 interfaces, see Line Cards Supported on the Cisco 12000 Router.
Cisco IOS Command Restrictions
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Link bundles that consist of Fast Ethernet interfaces are supported only on Engine 5 line cards, starting in Cisco IOS Release 12.0(33)S. You cannot combine ISE (Engine 3) ports with Engine 5 Fast Ethernet ports in a Fast EtherChannel.
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We do not recommend using static ARP and static routes, such as IP route 1.1.1.1 255.255.255.0 gig/1/1/0.
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For information about Engine 5 line card support for specific ASIC versions, refer to Supported Line Cards for the 12000 Series Routers in the Cross-Platform Release Notes for Cisco IOS Release 12.0S.
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Load-Balancing Restrictions
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VLAN Scalability Restrictions
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Supported Platforms
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Determining Platform Support Through Cisco Feature Navigator
Cisco IOS software is packaged in feature sets that are supported on specific platforms. To obtain updated information on platform support for this feature, access Cisco Feature Navigator. Cisco Feature Navigator dynamically updates as new platform support is added for a feature.
Cisco Feature Navigator is a web-based tool that enables you to determine which Cisco IOS software images support a specific set of features. You can search by feature or release. Under the release section, you can compare releases to display both the features unique to each software release and the features in common.
To access Cisco Feature Navigator, you must have an account on Cisco.com. If you forgot or lost your account information, send a blank e-mail to cco-locksmith@cisco.com. An automatic check verifies that your e-mail address is registered with Cisco.com. If the check is successful, account details with a new random password are e-mailed to you. Qualified users can establish an account on Cisco.com at:
For the most current information, go to the Cisco Feature Navigator home page at:
Availability of Cisco IOS Software Images
Platform support for particular Cisco IOS software releases is dependent on the availability of the software images for those platforms. Software images for some platforms may be deferred, delayed, or changed without notice.
Supported Standards, MIBs, and RFCs
Standards
No new or modified standards are supported by this feature.
MIBs
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To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator at:
http://tools.cisco.com/ITDIT/MIBS/servility/index
If Cisco MIB Locator does not support the MIB information that you need, you can view supported MIBs and download MIBs from the Cisco MIBs page at:
http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml
To access Cisco MIB Locator, you must have an account on Cisco.com. If you forgot or lost your account information, send a blank e-mail to cco-locksmith@cisco.com. An automatic check verifies that your e-mail address is registered with Cisco.com. If the check is successful, account details with a new random password are e-mailed to you. Qualified users can establish an account on Cisco.com at:
RFCs
No new or modified RFCs are supported by this feature.
Configuration Tasks
Configuring the Link Bundling (EtherChannel and POS channel) feature on Cisco 12000 series Internet routers consists of the following steps:
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After you configure an EtherChannel or POS channel, you can configure the out-of-service support and bandwidth propagation features on the link bundle interface.
See the following sections for configuration tasks for the Link Bundling feature. Each task in the list is identified as either optional or required.
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For information on other configuration tasks for EtherChannel and POS channel link bundling, refer to the Gigabit Ethernet and Packet-over-SONET sections in the "Configuring Interfaces" chapter of the Configuration Fundamentals Configuration Guide.
Configuring a Port-Channel Interface
You must configure a port-channel (logical) interface for each EtherChannel link bundle on the routers at each end of the channel (see the "Configuring an EtherChannel" section).
To configure a port-channel interface for an EtherChannel, perform the following steps beginning in global configuration mode:
Step 1
Router(config)# interface port-channel channel-number
Creates the port-channel (logical) interface to be used for the EtherChannel and enters interface configuration mode. The valid values for channel-number are 1 to 16.
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Router(config-if)# ip address ip-address mask
Assigns an IP address and subnet mask to the EtherChannel.
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Router(config-if)# mac address ieee-address
(Optional) Assigns a static MAC address to the EtherChannel.
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Router(config-if)# channel-group bandwidth control-propagation
(Optional) Enables the automatic propagation of bandwidth changes to upper-layer protocols for the bandwidth threshold specified by the threshold threshold-number parameter.
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Router(config-if)# channel-group bandwidth threshold threshold-number
(Optional) Specifies the maximum number of active member interfaces allowed in order for the total bandwidth used in the active members of an EtherChannel to be propagated to upper-layer protocols each time there is a change in bandwidth.
When a member interface is brought up and the number of active links exceeds the threshold number, the aggregate bandwidth of the active members is not propagated.
When the number of active members becomes one more than the threshold value, the aggregate bandwidth of all member interfaces (both active and passive) in the EtherChannel is propagated to upper-layer protocols.
Note that the channel-group bandwidth threshold threshold-number command is valid only after you enter the channel-group bandwidth control-propagation command.
Also, this value is not valid and a bandwidth change is not propagated if the EtherChannel is down because the minimum number of active member interfaces configured with the channel-group minimum active command are not operational.
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Router(config-if)# channel-group minimum active link-number
(Optional) Configures the minimum number of active members (GE links) that must be active in order for the EtherChannel to be operational. The valid values for link-number are from 1 to 8.
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Router(config-if)# channel-group load-share vlan
(Optional) Configures load-balancing across member interfaces based on the VLAN ID of transmitted packets.
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Router(config-if)# ios-command
(Optional) Enables other supported interface commands for the software features supported across the entire bundle (see the "Restrictions for Link Bundling" section).
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Router(config-if)# end
Exits from interface configuration mode.
Configuring a POS-Channel Interface
You must configure a pos-channel (logical) interface for each POS channel link bundle on the routers at each end of the POS channel (see the "Configuring a POS Channel" section).
To configure a pos-channel interface for a POS channel, perform the following steps beginning in global configuration mode:
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Router(config)# interface pos-channel channel-number
Creates the port-channel (logical) interface to be used for the POS channel and enters interface configuration mode. The valid values for channel-number are 1 to 16.
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Router(config-if)# ip address ip-address mask
Assigns an IP address and subnet mask to the POS channel.
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Router(config-if)# channel-group bandwidth control-propagation
(Optional) Enables the automatic propagation of bandwidth changes to upper-layer protocols for the bandwidth threshold specified by the threshold threshold-number parameter.
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Router(config-if)# channel-group bandwidth threshold threshold-number
(Optional) Specifies the maximum number of active member interfaces allowed in order for the total bandwidth used in the active members of a POS channel to be propagated to upper-layer protocols each time there is a change in bandwidth.
When a member interface goes up and the number of active links exceeds the threshold number, the aggregate bandwidth of the active members is not propagated.
When the number of active members becomes one more than the threshold value, the aggregate bandwidth of all member interfaces (both active and passive) in the POS channel is propagated to upper-layer protocols.
Note that the channel-group bandwidth threshold threshold-number command is valid only after you enter the channel-group bandwidth control-propagation command.
Also, this value is not valid and a bandwidth change is not propagated if the POS channel is down because the minimum number of active member interfaces configured with the channel-group minimum active command are not up.
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Router(config-if)# channel-group minimum active link-number
(Optional) Configures the minimum number of active members (POS links) that must be active in order for the POS channel to be up. The valid values for link-number are from 1 to 8.
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Router(config-if)# ios-command
(Optional) Enables other supported interface commands for the software features supported across the entire bundle (see the "Restrictions for Link Bundling" section).
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Router(config-if)# end
Exits from interface configuration mode.
Adding a Fast Ethernet or Gigabit Ethernet Interface
After you configure a port-channel interface on the router at one end of an EtherChannel, you can add up to 8 Fast Ethernet or Gigabit Ethernet interfaces to the EtherChannel group. The interfaces you add to the port-channel must be of the same engine number and media type. For example, a Gigabit EtherChannel can consist only of all Engine 1 GE interfaces or all Engine 2 GE interfaces. The interfaces you add to the port-channel can, however, belong to line cards in different slots.
You must add the same number of members (FE or GE interfaces) to the port-channel logical interface on the router at each end of an EtherChannel (see Configuring an EtherChannel).
To add a Fast Ethernet or Gigabit Ethernet interface to an EtherChannel bundle, perform the following steps beginning in global configuration mode:
Adding a Packet-over-SONET Interface
After you configure a pos-channel interface on the router at one end of a POS channel, you can add up to 8 Packet-over-SONET interfaces to the POS channel group. The interfaces you add to the POS channel must be of the same engine number and media type. For example, a POS channel can consist only of all Engine 0 POS interfaces or all Engine 2 POS interfaces. The interfaces you add can belong to POS line cards in different slots.
You must add the same number of members (POS interfaces) to the pos-channel logical interface on the router at each end of a POS channel (see the "Configuring a POS Channel" section).
To add a Packet-over-SONET (POS) interface to a POS channel bundle, perform the following steps beginning in global configuration mode:
Maximizing VLAN TCAM to Support VLAN Scalability
As you increase the number of VLANs configured on a port-channel interface (see VLAN Scalability), the performance of VLAN load-balancing and data transmission in an EtherChannel depends on the percentage of TCAM allocated for VLANs on each Fast Ethernet o r Gigabit Ethernet line card whose interfaces belong to the link bundle.
To display the amount of TCAM allocated for Cisco IOS features on an Ethernet line card, enter the show controllers frfab alpha tcam carve command.
To increase the VLAN TCAM size so that a maximum of 1K of TCAM is allocated to process VLAN traffic on each member subinterface, perform the following steps starting in global configuration mode:
Removing an Ethernet or Packet-over-SONET Interface from a Link Bundle
To remove a Fast Ethernet or Gigabit Ethernet interface from an EtherChannel bundle or a Packet-over-SONET interface from a POS channel bundle, perform the following steps beginning in global configuration mode:
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To monitor the status of an EtherChannel, use the show interfaces port-channel EXEC command. To monitor the status of a POS channel interface, use the show interfaces pos-channel command.
Configuring Out-of-Service Support
After you configure an EtherChannel (see the "Configuring a Port-Channel Interface" section) or a POS channel (see the "Configuring a POS-Channel Interface" section), you can specify the minimum number of active member interfaces required to be up and active for the link bundle to stay up or to come up if it is down. This is called out-of-service support and is an optional task.
Configure out-of-service support when you use link bundles that consist of two or more member interfaces and want to avoid overdriving the link bundle interface if a specified amount of bandwidth is not needed in the link bundle. The amount of bandwidth used by a link bundle is the combined amount of default bandwidth on each of its member interfaces.
You can specify a new value for the amount of bandwidth required for a link bundle by specifying the minimum number of active member links that must be up for the link bundle to be up. When a minimum number of member interfaces is not up, the link bundle interface goes down. The link bundle comes up from being out-of-service as soon as the required minimum number of member links become active.
To configure out-of-service support for an EtherChannel or POS channel bundle, perform the following steps beginning in global configuration mode:
Configuring Bandwidth Propagation
After you configure an EtherChannel (see the "Configuring a Port-Channel Interface" section) or a POS channel (see the "Configuring a POS-Channel Interface" section), you can also specify the upper bandwidth threshold to use for propagating bandwidth changes to upper-layer protocols. By default, at each change in bandwidth in a link bundle, the combined amount of bandwidth used on all active member links is propagated.
A bandwidth change in a link bundle occurs when any of the following events occur:
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The bandwidth threshold is specified according to the number of active member interfaces in the link bundle. When the required number of active member interfaces is less than or equal to the specified threshold number, the total amount of bandwidth used in the link bundle is propagated to upper-layer protocols at each bandwidth change. As soon as the number of active member links becomes greater than the specified threshold number, bandwidth changes are no longer propagated.
In addition, bandwidth changes are not propagated if the link bundle goes down because the number of active member interfaces is less than the configured minimum number of active member links required (see Configuring Out-of-Service Support).
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To configure an upper bandwidth threshold to use for propagating bandwidth changes in an EtherChannel or POS channel bundle to upper-layer protocols, perform the following steps beginning in global configuration mode:
Verifying an EtherChannel
To monitor the status of an EtherChannel, use the show interfaces port-channel command in privileged EXEC mode. The following output is for a Gigabit EtherChannel with three GE interfaces. All interfaces are up and therefore appear as active members of the channel. If one of the active interfaces goes down, it would be listed as a passive member. The status of a Gigabit EtherChannel is up if it has at least one active member interface.
Router# show interfaces port-channel 1Port-channel1 is up, line protocol is upHardware is GEChannel, address is 0050.2ac6.9581 (bia 0000.0000.0000)Internet address is 22.1.0.2/16MTU 1500 bytes, BW 3000000 Kbit, DLY 10 usec, rely 255/255, load 1/255Encapsulation ARPA, loopback not setKeepalive set (10 sec)ARP type: ARPA, ARP Timeout 04:00:00No. of active members in this channel: 3Member 0 : GigabitEthernet3/1 , Full-duplex, 1000Mb/sMember 1 : GigabitEthernet3/2 , Full-duplex, 1000Mb/sMember 2 : GigabitEthernet1/2 , Full-duplex, 1000Mb/sNo. of passive members in this channel: 0Last input 00:00:01, output 00:00:01, output hang neverLast clearing of "show interface" counters 3d15hQueueing strategy: fifoOutput queue 0/120, 0 drops; input queue 0/225, 0 drops30 second input rate 1425032000 bits/sec, 1038111 packets/sec30 second output rate 0 bits/sec, 0 packets/sec328903597021 packets input, 56454340092292 bytes, 0 no bufferReceived 50815 broadcasts, 0 runts, 0 giants, 0 throttles528238 input errors, 0 CRC, 0 frame, 528238 overrun, 0 ignored0 watchdog, 0 multicast, 0 pause input128365 packets output, 9409520 bytes, 0 underruns0 output errors, 0 collisions, 0 interface resets0 babbles, 0 late collision, 0 deferred0 lost carrier, 0 no carrier, 0 pause output0 output buffer failures, 0 output buffers swapped outVerifying a POS Channel
To monitor the status of a POS channel, use the show interfaces pos-channel command in privileged EXEC mode. The following output is for a POS channel with three POS interfaces.
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If an active member interface goes down, it is shown in the list of passive members. L
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Router# show interfaces pos-channel 1Pos-channel1 is up, line protocol is upHardware is POSChannelInternet address is 41.1.0.1/16MTU 4470 bytes, BW 1244000 Kbit, DLY 100 usec, rely 255/255, load 236/255Encapsulation HDLC, loopback not setKeepalive set (10 sec)No. of active members in this channel: 2Member 0 : POS5/0Member 1 : POS2/3No. of passive members in this channel: 1Member 0 : POS5/1Last input 00:00:01, output 00:00:03, output hang neverLast clearing of "show interface" counters 3d15hQueueing strategy: fifoOutput queue 0/80, 3665649311 drops; input queue 0/150, 0 drops30 second input rate 0 bits/sec, 0 packets/sec30 second output rate 1168138000 bits/sec, 627497 packets/sec192649 packets input, 12073574 bytes, 0 no bufferReceived 0 broadcasts, 0 runts, 0 giants, 0 throttles0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort197631584356 packets output, 46098596464843 bytes, 0 underruns0 output errors, 0 collisions, 0 interface resets0 output buffer failures, 0 output buffers swapped out0 carrier transitionsConfiguration Examples
This section provides the following configuration examples:
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Configuring an EtherChannel
The following is a sample configuration of an EtherChannel between two adjacent routers, in which three Gigabit Ethernet interfaces on each router are configured in the link bundle.
Router1# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Router1(config)# interface port-channel 1Router1(config-if)# ip address 22.1.0.1 255.255.0.0Router1(config-if)# exitRouter1(config)# interface gigabitethernet4/1Urbana(config-if)# channel-group 1Command will clear some config: IP address(es), loopbackManually remove other configsContinue? [yes]: yesGigabitEthernet4/1 added as member-1 to port-channel1GigabitEthernet4/1, cleared IP address and loopback modeRouter1(config)# interface gigabitethernet4/2Urbana(config-if)# channel-group 1Command will clear some config: IP address(es), loopbackManually remove other configsContinue? [yes]: yesGigabitEthernet4/2 added as member-2 to port-channel1GigabitEthernet4/2, cleared IP address and loopback modeRouter1(config)# interface gigabitethernet5/2Urbana(config-if)# channel-group 1Command will clear some config: IP address(es), loopbackManually remove other configs.Continue? [yes]: yesGigabitEthernet5/2 added as member-3 to port-channel1GigabitEthernet4/1, cleared IP address and loopback modeRouter1(config-if)# exitRouter2# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Router2(config)# interface port-channel 1Router2(config-if)# ip address 22.1.0.2 255.255.0.0Router2(config-if)# exitRouter2(config)# interface gigabitethernet3/1Urbana(config-if)# channel-group 1Command will clear some config: IP address(es), loopbackManually remove other configs.Continue? [yes]: yesGigabitEthernet3/1 added as member-1 to port-channel1GigabitEthernet3/1, cleared IP address and loopback modeRouter2(config)# interface gigabitethernet3/2Urbana(config-if)# channel-group 1Command will clear some config: IP address(es), loopbackManually remove other configs.Continue? [yes]: yesGigabitEthernet3/2 added as member-2 to port-channel1GigabitEthernet3/2, cleared IP address and loopback modeRouter2(config)# interface gigabitethernet1/2Urbana(config-if)# channel-group 1Command will clear some config: IP address(es), loopbackManually remove other configs.Continue? [yes]: yesGigabitEthernet1/2 added as member-3 to port-channel1GigabitEthernet1/2, cleared IP address and loopback modeRouter2(config-if)# exitThe following example shows how to verify EtherChannel connectivity by pinging each router.
Router1# ping 22.1.0.2Type escape sequence to abort.Sending 5, 100-byte ICMP Echos to 22.1.0.2, timeout is 2 seconds:!!!!!Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/4 msRouter2# ping 22.1.0.1Type escape sequence to abort.Sending 5, 100-byte ICMP Echos to 22.1.0.1, timeout is 2 seconds:!!!!!Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/4 msConfiguring a VLAN EtherChannel
The following shows a sample configuration of an EtherChannel that consists of two Ethernet 802.1q VLAN links. Bandwidth changes in Gigabit EtherChannel 6 are propagated to upper-layer protocols only when two or more member interfaces are up and active.
Router1# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Router1(config)# interface port-channel 6Router1(config-if)# channel-group minimum active 2Router1(config-if)# no channel-group bandwidth control-propagationRouter1(config-if)# exitRouter1(config)# interface port-channel 6.1Router1(config-if)# encapsulation dot1Q 1Router1(config-if)# ip address 21.1.6.7 255.255.255.0Router1(config-if)# exitRouter1(config)# interface port-channel 6.3Router1(config-if)# encapsulation dot1Q 2Router1(config-if)# ip address 21.1.6.7 255.255.255.0Router1(config-if)# exitRemoving an EtherChannel
The following example shows how to remove all GE interfaces and delete a Gigabit EtherChannel between two routers:
Router1(config)# no interface port-channel 1GigabitEthernet4/1 taken out of port-channel1GigabitEthernet5/2 taken out of port-channel1GigabitEthernet4/2 taken out of port-channel1Router2(config)# no interface port-channel 1GigabitEthernet3/1 taken out of port-channel1GigabitEthernet1/2 taken out of port-channel1GigabitEthernet3/2 taken out of port-channel1Configuring a POS Channel
The following is a sample configuration of a POS channel between two adjacent routers in which three Packet-over-SONET interfaces on each router are configured in the link bundle.
Router1# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Router1(config)# interface pos-channel 1Router1(config-if)# ip address 41.1.0.1 255.255.0.0Router1(config-if)# exitRouter1(config)# interface pos5/0Urbana(config-if)# channel-group 1Command will clear some config: IP address(es), loopbackManually remove other configs.Continue? [yes]: yesPOS5/0 added as member-1 to POS-channel1POS5/0, cleared IP address and loopback modeRouter1(config)# interface pos5/1Urbana(config-if)# channel-group 1Command will clear some config: IP address(es), loopbackManually remove other configs.Continue? [yes]: yesPOS5/1 added as member-2 to port-channel1POS5/1, cleared IP address and loopback modeRouter1(config)# interface pos2/3Urbana(config-if)# channel-group 1Command will clear some config: IP address(es), loopbackManually remove other configs.Continue? [yes]: yesPOS2/3 added as member-3 to port-channel1POS2/3, cleared IP address and loopback modeRouter1(config-if)# exitRouter2# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Router2(config)# interface pos-channel 1Router2(config-if)# ip address 41.1.0.2 255.255.0.0Router2(config-if)# exitRouter2(config)# interface pos5/0Urbana(config-if)# channel-group 1Command will clear some config: IP address(es), loopbackManually remove other configs.Continue? [yes]: yesPOS5/0 added as member-1 to POS-channel1POS5/0, cleared IP address and loopback modeRouter2(config)# interface pos5/1Urbana(config-if)# channel-group 1Command will clear some config: IP address(es), loopbackManually remove other configs.Continue? [yes]: yesPOS5/1 added as member-2 to port-channel1POS5/1, cleared IP address and loopback modeRouter2(config)# interface pos5/3Urbana(config-if)# channel-group 1Command will clear some config: IP address(es), loopbackManually remove other configs.Continue? [yes]: yesPOS5/3 added as member-3 to port-channel1POS5/3, cleared IP address and loopback modeThe following example shows how to verify POS channel connectivity by pinging each router.
Router1# ping 41.1.0.2Type escape sequence to abort.Sending 5, 100-byte ICMP Echos to 41.1.0.2, timeout is 2 seconds:!!!!!Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 msRouter2# ping 41.1.0.1Type escape sequence to abort.Sending 5, 100-byte ICMP Echos to 41.1.0.1, timeout is 2 seconds:!!!!!Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/4 msRemoving a POS Channel
The following example shows how to remove all POS interfaces and delete a POS channel between 2 routers:
Router1(config)# no interface pos-channel 1POS5/0 taken out of Poschannel1POS2/3 taken out of Poschannel1Router2(config)# no interface pos-channel 1POS5/0 taken out of Poschannel1POS5/3 taken out of Poschannel1Configuring Out-of-Service Support
The following example shows how to configure out-of-service support for an EtherChannel so that the following events occur:
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Router1# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Router1(config)# interface port-channel 1Router1(config-if)# channel-group minimum active 2Router1(config-if)# exitConfiguring Bandwidth Propagation
The following example shows how to control the propagation of bandwidth changes and configure a bandwidth threshold on an EtherChannel so that as long as up to 4 member interfaces are up and active, the total amount of bandwidth used by the active members in the link bundle is propagated to upper-layer protocols at each bandwidth changes.
Note that this example assumes that there are seven member interfaces and that 2 or more active member interfaces are required for the EtherChannel to be up, as shown in the example for Configuring Out-of-Service Support.
Router1# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Router1(config)# interface port-channel 1Router1(config-if)# channel-group bandwidth control-propagationRouter1(config-if)# channel-group bandwidth threshold 4Router1(config-if)# exitFor the EtherChannel in the preceding example, bandwidth changes are propagated to upper-layer protocols as long as two, three, four, or five member interfaces are active:
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As soon as one member interface more than the configured threshold value becomes active (in this example, 5 interfaces), the total bandwidth propagated to upper-layer protocols is the combined total of all member interfaces in the link bundle (in this example, 7 interfaces or 7 Gigabits).
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Command Reference
This section documents new commands. All other commands used with this feature are documented in the Cisco IOS Release 12.0 command reference publications.
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channel-group
To assign a Fast Ethernet or Gigabit Ethernet interface to an EtherChannel or a Packet-over-SONET interface to a POS channel link bundle, use the channel-group command in interface configuration mode. To remove an interface from an EtherChannel or POS channel, use the no form of this command.
channel-group channel-number
no channel-group channel-number
Use the channel-group command in interface configuration mode for an EtherChannel or Packet-over-SONET channel interface to perform the following tasks:
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To restore the default (minimum number of active links required or bandwidth propagation) settings for an EtherChannel or POS channel, use the no form of the following commands. These channel-group commands cannot be used for a Fast Ethernet, Gigabit Ethernet, or Packet-over-SONET member interface.
channel-group minimum active link-number
no channel-group minimum active link-number
channel-group bandwidth control-propagation
no channel-group bandwidth control-propagation
channel-group bandwidth threshold threshold-number
no channel-group bandwidth threshold threshold-number
channel-group load-share vlan
no channel-group load-share vlan
Syntax Description
Defaults
No channel group is assigned.
The default number of minimum active links required in an EtherChannel or POS channel is 1.
Bandwidth changes are propagated, by default, to upper-layer protocols.
The default load-balancing in an EtherChannel is to balance outgoing traffic across all member links according to the source and destination IP address of transmitted packets.
Command Modes
Interface configuration mode
Command History
Usage Guidelines
Configuring an EtherChannel
Before you assign a FE or GE interface to an EtherChannel, you must first create a port-channel logical interface using the interface port-channel command in global configuration mode. After you configure a port-channel interface on the router at one end of an EtherChannel, you use the channel-group command to add up to eight Fast Ethernet or Gigabit Ethernet interfaces to the EtherChannel group.
The interfaces you add to the port-channel must be of the same Engine number and media type. For example, a Gigabit EtherChannel can consist only of all Engine 1 GE interfaces or all Engine 2 GE interfaces. The interfaces you add to the port-channel can, however, belong to line cards in different slots.
You must add the same number of FE or GE member interfaces to the port-channel logical interface on the router at each end of an EtherChannel (see the "Configuring an EtherChannel" section).
If the FE or GE interface already has an IP address assigned, you must disable it before adding the interface to an EtherChannel or POS channel. You are prompted to disable the IP address and other configuration settings after you enter the channel-group command. To disable the IP address, type yes at the prompt.
Note
To display information about an EtherChannel, use the show interfaces port-channel command in privileged EXEC mode.
Configuring a POS Channel
Before you assign a POS interface to a POS channel, you must first create a pos-channel logical interface using the interface pos-channel command in global configuration mode. After you configure a pos-channel interface on the router at one end of a POS channel, you use the channel-group command to add up to eight POS interfaces to the POS channel group.
The interfaces you add to the pos-channel must be of the same Engine number and media type. For example, a POS channel can consist only of all Engine 0 POS interfaces or all Engine 2 POS interfaces. The interfaces you add to the pos-channel can, however, belong to line cards in different slots.
You must add the same number of POS member interfaces to the pos-channel logical interface on the router at each end of a POS channel (see the "Configuring a POS Channel" section). If the POS interface already has an IP address assigned, you must disable it before adding the interface to a POS channel. You are prompted to disable the IP address and other configuration settings after you enter the channel-group command. To disable the IP address, type yes at the prompt.
Note
To view information about a POS channel, use the show interfaces pos-channel command in privileged EXEC mode.
Out-of-Service Support
Use the channel-group minimum active link-number command in interface configuration mode for an EtherChannel or POS channel interface to configure the minimum number of active member links that must be up and active in order for the link bundle to stay up.
For example, you can have an EtherChannel that consists of eight Gigabit Ethernet links. By default (that is, if you do not use the bandwidth command to configure the amount of available bandwidth), the EtherChannel uses eight gigabits of bandwidth; one gigabit is reserved for each Gigabit Ethernet member interface. However, to avoid overdriving the channel if the amount of required bandwidth falls below three gigabits, you can use the channel-group minimum active 3 command to specify that the EtherChannel is brought down if fewer than three member links are active.
Bandwidth Propagation
Use the channel-group bandwidth control-propagation command in interface configuration mode for an EtherChannel or POS channel interface (see the "interface port-channel" section and the "interface pos-channel" section) to enable and disable the default propagation of the amount of bandwidth used in a link bundle to upper-layer protocols each time there is a bandwidth change. This command allows you to manually control (turn on and off) the propagation of bandwidth changes for the bandwidth threshold specified by the channel-group bandwidth threshold threshold-number command.
Note
A bandwidth change in a link bundle occurs when any of the following events occur:
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The bandwidth threshold is specified according to the number of active member interfaces in the link bundle. When the required number of active member interfaces is less than or equal to the specified threshold number, the total amount of bandwidth used on active members in the link bundle is propagated to upper-layer protocols at each bandwidth change.
When a member interface goes up and the number of active links exceeds the threshold number, the aggregate bandwidth of the active members is not propagated.
When the number of active members becomes one more than the threshold value, the aggregate bandwidth of all member interfaces (both active and passive) in the bundle is propagated to upper-layer protocols.
In addition, bandwidth changes are not propagated if the link bundle goes down because the number of active member interfaces is less than the configured minimum number of active member links required, as described in the "Out-of-Service Support" section.
Note
The bandwidth command is supported on a member interface only after you remove it from the link bundle. The bandwidth of the link bundle is then reduced by the default bandwidth of the interface that you removed.EtherChannel Load-balancing
To configure load-balancing in the link bundle based on the VLAN ID of transmitted packets, use the channel-group load-share vlan command in interface configuration mode for an EtherChannel (port-channel) interface. Outgoing traffic is normally balanced across all links in a bundle based on the source and destination IP address of packets. To switch back to per-destination load-balancing, use the no channel-group load-share vlan command.
VLAN ID-based load sharing is recommended in an EtherChannel bundle in the following configurations:
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Examples
The following example adds a Gigabit Ethernet interface to the EtherChannel bundle specified by port-channel 1:
Router(config)# interface port-channel 1Router(config-if)# ip address 22.1.0.1 255.255.255.0Router(config-if)# endRouter(config)# interface gigabitethernet 1/0Router(config-if)# channel-group 1The next example shows how to configure the automatic propagation of bandwidth changes in the EtherChannel only when two, three or four Gigabit Ethernet member interfaces are up and active:
Router(config)# interface port-channel 1Router(config-if)# channel-group minimum active 2Router(config-if)# channel-group bandwidth control-propagationRouter(config-if)# channel-group bandwidth threshold 4This example shows how to configure load-balancing across member links of an EtherChannel based on the VLAN ID of transmitted packets:
Router(config)# interface port-channel 2Router(config-if)# channel-group load-share vlanRelated Commands
hw-module slot linkbundle-tcam-scalability
To maximize the amount of VLAN TCAM allocated to process VLAN traffic on a Fast Ethernet or Gigabit Ethernet line card whose interfaces belong to an EtherChannel link bundle, use the hw-module slot linkbundle-tcam-scalability command in global configuration mode. To restore the default VLAN TCAM size, use the no form of this command.
hw-module slot number linkbundle-tcam-scalability
Syntax Description
Defaults
No default behavior or values.
Command Modes
Global configuration
Command History
Usage Guidelines
When you increase the number of VLANs on the member interfaces of an EtherChannel, the performance of VLAN load-balancing and data transmission depends on the percentage of ternary content addressable memory (TCAM) allocated for VLANs on each Fast Ethernet or Gigabit Ethernet line card, whose interfaces belong to the link bundle.The hw-module slot linkbundle-tcam-scalability command allows you to recarve Layer 2 TCAM regions so that 1K of TCAM is allocated to process VLAN traffic on each subinterface used in a link bundle.
To display the amount of TCAM allocated for Cisco IOS features on a line card, enter the show controllers frfab alpha tcam carve command.
After you enter the hw-module slot linkbundle-tcam-scalability command, you must enter the microcode reload command to reload the software and microcode on the line card so that the newly configured VLAN TCAM size take effect.
Examples
The following example shows how to maximize the VLAN TCAM allocated to member subinterfaces on the Gigabit Ethernet line card in slot 3:
Router(config)# hw-module slot 3 linkbundle-tcam-scalability
Router(config)# microcode reload 3
Related Commands
show controllers frfab alpha tcam carve
Displays the amount of TCAM allocated to Cisco IOS features on a line card.
interface port-channel
To specify a port-channel interface to associate with an EtherChannel and enter interface configuration mode, use the interface port-channel command in global configuration mode. To delete all interfaces from an EtherChannel, use the no form of this command.
interface port-channel channel-number
no interface port-channel channel-number
Syntax Description
Defaults
No default behavior or values.
Command Modes
Global configuration mode
Command History
Usage Guidelines
The Cisco 12000 series Link Bundling feature allows you to bundle multiple Fast Ethernet or Gigabit Ethernet point-to-point links into one logical link to provide higher bidirectional bandwidth. You can configure an EtherChannel between the following routers:
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Using the interface port-channel command, you configure the port-channel (logical) interface associated with an EtherChannel link bundle. Using the channel-group command, you then add up to eight Fast Ethernet or Gigabit Ethernet interfaces to an EtherChannel group.
You must configure the port-channel (logical) interface on the router at each end of the EtherChannel (see the "Configuring an EtherChannel" section). You can configure a different port-channel number on each router.
To display information about an EtherChannel, use the show interfaces port-channel command in privileged EXEC mode.
To delete the counters for one or all Cisco 12000 series FE or GE interfaces in an EtherChannel link bundle, use the clear counters command in privileged EXEC mode.
Note
Examples
The following example creates a port-channel interface for an EtherChannel bundle with a channel group number of 1:
router# configure terminalrouter(config)# interface port-channel 1router(config-if)# ip address 22.1.0.1 255.255.0.0router(config-if)# endRelated Commands
interface pos-channel
To specify a pos-channel interface to associate with a POS channel link bundle and enter interface configuration mode, use the interface pos-channel command in global configuration mode. To delete all interfaces from a POS channel, use the no form of this command.
interface pos-channel channel-number
no interface pos-channel channel-number
Syntax Description
Defaults
No default behavior or values.
Command Modes
Global configuration mode
Command History
Usage Guidelines
The Link Bundling feature allows you to bundle multiple Packet-over-SONET point-to-point links into one logical link to provide higher bidirectional bandwidth. You can configure a POS channel between the following routers:
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Using the interface pos-channel command, you configure the pos-channel (logical) interface associated with a POS channel link bundle. Using the channel-group command, you then add up to 8 packet over SONET interfaces to a POS channel group.
You must configure the pos-channel (logical) interface on the router at each end of the POS channel (see the "Configuring a POS Channel" section). You can configure a different pos-channel number on each router.
To display information about a POS channel, use the show interfaces pos-channel command in privileged EXEC mode.
To delete the counters for one or all POS interfaces in a POS channel link bundle, use the clear counters command in privileged EXEC mode.
Examples
The following example creates a pos-channel interface for a POS channel bundle with a channel group number of 3:
router# configure terminalrouter(config)# interface pos-channel 3router(config-if)# ip address 23.1.0.1 255.255.0.0router(config-if)# endRelated Commands
show interfaces port-channel
To display information about an EtherChannel, use the show interfaces port-channel command in privileged EXEC configuration mode.
show interfaces port-channel channel-number
Syntax Description
channel-number
Port channel number associated with an EtherChannel. The valid values are from 1 to 16.
Defaults
No default behavior or values.
Command Modes
Privileged EXEC
Command History
Usage Guidelines
Use the show interfaces port-channel command to display information about the bundled FE or GE links in an EtherChannel.
Examples
The following example shows sample output for a Cisco 12000 series EtherChannel.
Router# show interfaces port-channel 1Port-channel1 is up, line protocol is upHardware is GEChannel, address is 0050.2ac6.9581 (bia 0000.0000.0000)Internet address is 22.1.0.2/16MTU 1500 bytes, BW 3000000 Kbit, DLY 10 usec, rely 255/255, load 1/255Encapsulation ARPA, loopback not setKeepalive set (10 sec)ARP type: ARPA, ARP Timeout 04:00:00No. of active members in this channel: 3Member 0 : GigabitEthernet3/1 , Full-duplex, 1000Mb/sMember 1 : GigabitEthernet3/2 , Full-duplex, 1000Mb/sMember 2 : GigabitEthernet1/2 , Full-duplex, 1000Mb/sNo. of passive members in this channel: 0Last input 00:00:01, output 00:00:01, output hang neverLast clearing of "show interface" counters 3d15hQueueing strategy: fifoOutput queue 0/120, 0 drops; input queue 0/225, 0 drops30 second input rate 1425032000 bits/sec, 1038111 packets/sec30 second output rate 0 bits/sec, 0 packets/sec328903597021 packets input, 56454340092292 bytes, 0 no bufferReceived 50815 broadcasts, 0 runts, 0 giants, 0 throttles528238 input errors, 0 CRC, 0 frame, 528238 overrun, 0 ignored0 watchdog, 0 multicast, 0 pause input128365 packets output, 9409520 bytes, 0 underruns0 output errors, 0 collisions, 0 interface resets0 babbles, 0 late collision, 0 deferred0 lost carrier, 0 no carrier, 0 pause output0 output buffer failures, 0 output buffers swapped outTable 5 lists field descriptions for the show interfaces port-channel command.
Table 5 show interfaces port-channel Field Descriptions
Related Commands
interface port-channel
Specifies an EtherChannel and enters interface configuration mode.
show interfaces pos-channel
To display information about a POS channel, use the show interfaces pos-channel command in privileged EXEC configuration mode.
show interfaces pos-channel channel-number
Syntax Description
channel-number
Port channel number associated with a POS channel. The valid values are from 1 to 16.
Defaults
No default behavior or values.
Command Modes
Privileged EXEC
Command History
Usage Guidelines
Use the show interfaces pos-channel command to display information about the bundled POS links in a POS channel.
Examples
The following example shows sample output for a Cisco 12000 series POS channel.
Router# show interfaces pos-channel 1Pos-channel1 is up, line protocol is upHardware is POSChannelInternet address is 41.1.0.1/16MTU 4470 bytes, BW 1244000 Kbit, DLY 100 usec, rely 255/255, load 236/255Encapsulation HDLC, loopback not setKeepalive set (10 sec)No. of active members in this channel: 2Member 0 : POS5/0Member 1 : POS2/3No. of passive members in this channel: 1Member 0 : POS5/1Last input 00:00:01, output 00:00:03, output hang neverLast clearing of "show interface" counters 3d15hQueueing strategy: fifoOutput queue 0/80, 3665649311 drops; input queue 0/150, 0 drops30 second input rate 0 bits/sec, 0 packets/sec30 second output rate 1168138000 bits/sec, 627497 packets/sec192649 packets input, 12073574 bytes, 0 no bufferReceived 0 broadcasts, 0 runts, 0 giants, 0 throttles0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort197631584356 packets output, 46098596464843 bytes, 0 underruns0 output errors, 0 appliques, 0 interface resets0 output buffer failures, 0 output buffers swapped out0 carrier transitionsTable 6 lists field descriptions for the show interfaces pos-channel command.
Table 6 show interfaces pos-channel Field Descriptions
Related Commands
interface pos-channel
Specifies a POS channel and enters interface configuration mode.
Glossary
active member—Member interface of an EtherChannel or POS channel whose link status is up and can pass traffic.
ALPHA—Packet-switching ASIC on Cisco 12000 series IP Service Engine (ISE) line cards.
ASIC—application specific integrated circuit. Circuit designs used by manufacturers to consolidate many chips into a single package, reducing board size and power consumption.
EtherChannel—Developed and copyrighted by Cisco Systems. Logical aggregation of multiple Ethernet interfaces used to form a single higher bandwidth routing or bridging endpoint.
Fast EtherChannel members—Fast Ethernet interfaces (both active and passive) added to an EtherChannel.
Gbps—Gigabits per second.
Gigabit EtherChannel members—Gigabit Ethernet interfaces (both active and passive) added to an EtherChannel.
IOS—Cisco IOS software is an innovative and feature-rich network systems software that gives networks intelligence and agility. It allows the effective deployment of new applications and services that enable our customers's business to generate revenue, reduce costs and improve customer service.
link—In the context of a transmission network, a link is a point-to-point connection between adjacent nodes. There can be more than one link between adjacent nodes.
link bundle—Synonym for EtherChannel or POS channel.
passive member—Member interface of an EtherChannel or POS channel whose link status is down and cannot pass traffic.
point-to-point connection—One of two fundamental connection types. Communication between one receiver and one location.
POP—Point of presence. In an Operations Support System (OSS), a physical location where an interexchange carrier installed equipment to interconnect with a local exchange carrier (LEC).
port-channel—Type of interface in Cisco IOS software used to group Fast Ethernet and Gigabit Ethernet interfaces.
POS—Packet-over-SONET. A technology in which IP packets are mapped into SONET frames with intervening use of an ATM layer.
pos-channel—Type of interface in Cisco IOS software used to group Packet-over-SONET interfaces.
POS channel members—POS interfaces (both active and passive) added to a POS channel.
PSA—Packet-switching ASIC on Cisco 12000 series line cards.
Cisco and the Cisco Logo are trademarks of Cisco Systems, Inc. and/or its affiliates in the U.S. and other countries. A listing of Cisco's trademarks can be found at www.cisco.com/go/trademarks. Third party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1005R)
Copyright © 2008 Cisco Systems, Inc. All rights reserved.
