Table Of Contents
Configuring Routing Between VLANs
Information About Routing Between VLANs
Virtual Local Area Network Definition
Integrated Routing and Bridging
ATM LANE Fast Simple Server Replication Protocol
How to Configure Routing Between VLANS
Configuring a Range of VLAN Subinterfaces
Configuring Routing Between VLANs with Inter-Switch Link Encapsulation
Configuring AppleTalk Routing over ISL
Configuring Banyan VINES Routing over ISL
Configuring DECnet Routing over ISL
Configuring the Hot Standby Router Protocol over ISL
Configuring IP Routing over TRISL
Configuring IPX Routing on 802.10 VLANs over ISL
Configuring IPX Routing over TRISL
Configuring VIP Distributed Switching over ISL
Configuring XNS Routing over ISL
Configuring CLNS Routing over ISL
Configuring IS-IS Routing over ISL
Configuring Routing Between VLANs with IEEE 802.10 Encapsulation
Configuring Routing Between VLANs with IEEE 802.1Q Encapsulation
Configuring AppleTalk Routing over IEEE 802.1Q
Configuring IP Routing over IEEE 802.1Q
Configuring IPX Routing over IEEE 802.1Q
Configuring a VLAN for a Bridge Group with Default VLAN1
Configuring a VLAN for a Bridge Group as a Native VLAN
Configuring IEEE 802.1Q-in-Q VLAN Tag Termination
IEEE 802.1Q-in-Q VLAN Tag Termination on Subinterfaces
Cisco 10000 Series Internet Router Application
Security ACL Application on the Cisco 10000 Series Internet Router
Unambiguous and Ambiguous Subinterfaces
Configuring EtherType Field for Outer VLAN Tag Termination
Configuring the Q-in-Q Subinterface
Verifying the IEEE 802.1Q-in-Q VLAN Tag Termination
Monitoring and Maintaining VLAN Subinterfaces
Configuration Examples for Configuring Routing Between VLANs
Single Range Configuration: Example
ISL Encapsulation Configuration: Examples
AppleTalk Routing over ISL Configuration: Example
Banyan VINES Routing over ISL Configuration: Example
DECnet Routing over ISL Configuration: Example
HSRP over ISL Configuration: Example
IP Routing with RIF Between TrBRF VLANs: Example
IP Routing Between a TRISL VLAN and an Ethernet ISL VLAN: Example
IPX Routing over ISL Configuration: Example
IPX Routing on FDDI Interfaces with SDE: Example
Routing with RIF Between a TRISL VLAN and a Token Ring Interface: Example
VIP Distributed Switching over ISL Configuration: Example
XNS Routing over ISL Configuration: Example
CLNS Routing over ISL Configuration: Example
IS-IS Routing over ISL Configuration: Example
Routing IEEE 802.10 Configuration: Example
IEEE 802.1Q Encapsulation Configuration: Examples
Configuring AppleTalk over IEEE 802.1Q: Example
Configuring IP Routing over IEEE 802.1Q: Example
Configuring IPX Routing over IEEE 802.1Q: Example
VLAN 100 for Bridge Group 1 with Default VLAN1: Example
VLAN 20 for Bridge Group 1 with Native VLAN: Example
VLAN ISL or IEEE 802.1Q Routing: Example
VLAN IEEE 802.1Q Bridging: Example
Configuring IEEE 802.1Q-in-Q VLAN Tag Termination: Example
Feature Information for Routing Between VLANs
Configuring Routing Between VLANs
First Published: March 15, 2006Last Updated: October 10, 2008This module provides an overview of VLANs. It describes the encapsulation protocols used for routing between VLANs and provides some basic information about designing VLANs. This module contains tasks for configuring routing between VLANS.
Finding Feature Information in This Module
Your Cisco IOS software release may not support all of the features documented in this module. To reach links to specific feature documentation in this module and to see a list of the releases in which each feature is supported, use the "Feature Information for Routing Between VLANs" section.
Finding Support Information for Platforms and Cisco IOS Software Images
Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://www.cisco.com/go/fn. You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.
Contents
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Information About Routing Between VLANs
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Information About Routing Between VLANs
This module describes routing between VLANs. It contains the following sections:
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Virtual Local Area Network Definition
A virtual local area network (VLAN) is a switched network that is logically segmented on an organizational basis, by functions, project teams, or applications rather than on a physical or geographical basis. For example, all workstations and servers used by a particular workgroup team can be connected to the same VLAN, regardless of their physical connections to the network or the fact that they might be intermingled with other teams. Reconfiguration of the network can be done through software rather than by physically unplugging and moving devices or wires.
A VLAN can be thought of as a broadcast domain that exists within a defined set of switches. A VLAN consists of a number of end systems, either hosts or network equipment (such as bridges and routers), connected by a single bridging domain. The bridging domain is supported on various pieces of network equipment; for example, LAN switches that operate bridging protocols between them with a separate bridge group for each VLAN.
VLANs are created to provide the segmentation services traditionally provided by routers in LAN configurations. VLANs address scalability, security, and network management. Routers in VLAN topologies provide broadcast filtering, security, address summarization, and traffic flow management. None of the switches within the defined group will bridge any frames, not even broadcast frames, between two VLANs. Several key issues described in the following sections need to be considered when designing and building switched LAN internetworks:
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LAN Segmentation
VLANs allow logical network topologies to overlay the physical switched infrastructure such that any arbitrary collection of LAN ports can be combined into an autonomous user group or community of interest. The technology logically segments the network into separate Layer 2 broadcast domains whereby packets are switched between ports designated to be within the same VLAN. By containing traffic originating on a particular LAN only to other LANs in the same VLAN, switched virtual networks avoid wasting bandwidth, a drawback inherent to traditional bridged and switched networks in which packets are often forwarded to LANs with no need for them. Implementation of VLANs also improves scalability, particularly in LAN environments that support broadcast- or multicast-intensive protocols and applications that flood packets throughout the network.
Figure 73 illustrates the difference between traditional physical LAN segmentation and logical VLAN segmentation.
Figure 73 LAN Segmentation and VLAN Segmentation
Security
VLANs improve security by isolating groups. High-security users can be grouped into a VLAN, possibly on the same physical segment, and no users outside that VLAN can communicate with them.
Broadcast Control
Just as switches isolate collision domains for attached hosts and only forward appropriate traffic out a particular port, VLANs provide complete isolation between VLANs. A VLAN is a bridging domain, and all broadcast and multicast traffic is contained within it.
VLAN Performance
The logical grouping of users allows an accounting group to make intensive use of a networked accounting system assigned to a VLAN that contains just that accounting group and its servers. That group's work will not affect other users. The VLAN configuration improves general network performance by not slowing down other users sharing the network.
Network Management
The logical grouping of users allows easier network management. It is not necessary to pull cables to move a user from one network to another. Adds, moves, and changes are achieved by configuring a port into the appropriate VLAN.
Network Monitoring Using SNMP
SNMP support has been added to provide mib-2 interfaces sparse table support for Fast Ethernet subinterfaces. Monitor your VLAN subinterface using the show vlans EXEC command. For more information on configuring SNMP on your Cisco network device or enabling an SNMP agent for remote access, refer to the "Configuring SNMP" chapter in the Cisco IOS Configuration Fundamentals Configuration Guide.
Communication Between VLANs
Communication between VLANs is accomplished through routing, and the traditional security and filtering functions of the router can be used. Cisco IOS software provides network services such as security filtering, quality of service (QoS), and accounting on a per-VLAN basis. As switched networks evolve to distributed VLANs, Cisco IOS software provides key inter-VLAN communications and allows the network to scale.
Before Cisco IOS Release 12.2, Cisco IOS support for interfaces that have 802.1Q encapsulation configured is IP, IP multicast, and IPX routing between respective VLANs represented as subinterfaces on a link. New functionality has been added in IEEE 802.1Q support for bridging on those interfaces and the capability to configure and use integrated routing and bridging (IRB).
Relaying Function
The relaying function level, as displayed in Figure 74, is the lowest level in the architectural model described in the IEEE 802.1Q standard and presents three types of rules:
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Figure 74 Relaying Function
The Tagging Scheme
Figure 75 shows the tagging scheme proposed by the 802.3ac standard, that is, the addition of the four octets after the source MAC address. Their presence is indicated by a particular value of the EtherType field (called TPID), which has been fixed to be equal to 0x8100. When a frame has the EtherType equal to 0x8100, this frame carries the tag IEEE 802.1Q/802.1p. The tag is stored in the following two octets and it contains 3 bits of user priority, 1 bit of Canonical Format Identifier (CFI), and 12 bits of VLAN ID (VID). The 3 bits of user priority are used by the 802.1p standard; the CFI is used for compatibility reasons between Ethernet-type networks and Token Ring-type networks. The VID is the identification of the VLAN, which is basically used by the 802.1Q standard; being on 12 bits, it allows the identification of 4096 VLANs.
After the two octets of TPID and the two octets of the Tag Control Information field there are two octets that originally would have been located after the Source Address field where there is the TPID. They contain either the MAC length in the case of IEEE 802.3 or the EtherType in the case of Ethernet version 2.
Figure 75 Tagging Scheme
The EtherType and VLAN ID are inserted after the MAC source address, but before the original Ethertype/Length or Logical Link Control (LLC). The 1-bit CFI included a T-R Encapsulation bit so that Token Ring frames can be carried across Ethernet backbones without using 802.1H translation.
Frame Control Sequence Recomputation
Figure 76 shows how adding a tag in a frame recomputes the Frame Control Sequence. 802.1p and 802.1Q share the same tag.
Figure 76 Adding a Tag Recomputes the Frame Control Sequence
Native VLAN
Each physical port has a parameter called PVID. Every 802.1Q port is assigned a PVID value that is of its native VLAN ID (default is VLAN 1). All untagged frames are assigned to the LAN specified in the PVID parameter. When a tagged frame is received by a port, the tag is respected. If the frame is untagged, the value contained in the PVID is considered as a tag. Because the frame is untagged and the PVID is tagged to allow the coexistence, as shown in Figure 77, on the same pieces of cable of VLAN-aware bridge/stations and of VLAN-unaware bridges/stations. Consider, for example, the two stations connected to the central trunk link in the lower part of Figure 77. They are VLAN-unaware and they will be associated to the VLAN C, because the PVIDs of the VLAN-aware bridges are equal to VLAN C. Because the VLAN-unaware stations will send only untagged frames, when the VLAN-aware bridge devices receive these untagged frames they will assign them to VLAN C.
Figure 77 Native VLAN
PVST+
PVST+ provides support for 802.1Q trunks and the mapping of multiple spanning trees to the single spanning tree of 802.1Q switches.
The PVST+ architecture distinguishes three types of regions:
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Each region consists of a homogenous type of switch. A PVST region can be connected to a PVST+ region by connecting two ISL ports. Similarly, a PVST+ region can be connected to an MST region by connecting two 802.1Q ports.
At the boundary between a PVST region and a PVST+ region the mapping of spanning trees is one-to-one. At the boundary between a MST region and a PVST+ region, the ST in the MST region maps to one PVST in the PVST+ region. The one it maps to is called the common spanning tree (CST). The default CST is the PVST of VLAN 1 (Native VLAN).
All PVSTs, except for the CST, are tunneled through the MST region. Tunneling means that bridge protocol data units (BPDUs) are flooded through the MST region along the single spanning tree present in the MST region.
Ingress and Egress Rules
The BPDU transmission on the 802.1Q port of a PVST+ router will be implemented in compliance with the following rules:
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The BPDU reception on the 802.1Q port of a PVST+ router will follow these rules:
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Integrated Routing and Bridging
IRB enables a user to route a given protocol between routed interfaces and bridge groups or route a given protocol between the bridge groups. Integrated routing and bridging is supported on the following protocols:
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VLAN Colors
VLAN switching is accomplished through frame tagging where traffic originating and contained within a particular virtual topology carries a unique VLAN ID as it traverses a common backbone or trunk link. The VLAN ID enables VLAN switching devices to make intelligent forwarding decisions based on the embedded VLAN ID. Each VLAN is differentiated by a color, or VLAN identifier. The unique VLAN ID determines the frame coloring for the VLAN. Packets originating and contained within a particular VLAN carry the identifier that uniquely defines that VLAN (by the VLAN ID).
The VLAN ID allows VLAN switches and routers to selectively forward packets to ports with the same VLAN ID. The switch that receives the frame from the source station inserts the VLAN ID and the packet is switched onto the shared backbone network. When the frame exits the switched LAN, a switch strips the header and forwards the frame to interfaces that match the VLAN color. If you are using a Cisco network management product such as VlanDirector, you can actually color code the VLANs and monitor VLAN graphically.
Implementing VLANS
Network managers can logically group networks that span all major topologies, including high-speed technologies such as, ATM, FDDI, and Fast Ethernet. By creating virtual LANs, system and network administrators can control traffic patterns and react quickly to relocations and keep up with constant changes in the network due to moving requirements and node relocation just by changing the VLAN member list in the router configuration. They can add, remove, or move devices or make other changes to network configuration using software to make the changes.
Issues regarding creating VLANs should have been addressed when you developed your network design. Issues to consider include the following:
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Communication Between VLANs
Cisco IOS software provides full-feature routing at Layer 3 and translation at Layer 2 between VLANs. Five different protocols are available for routing between VLANs:
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All five of these technologies are based on OSI Layer 2 bridge multiplexing mechanisms.
Inter-Switch Link Protocol
The Inter-Switch Link (ISL) protocol is used to interconnect two VLAN-capable Ethernet, Fast Ethernet, or Gigabit Ethernet devices, such as the Catalyst 3000 or 5000 switches and Cisco 7500 routers. The ISL protocol is a packet-tagging protocol that contains a standard Ethernet frame and the VLAN information associated with that frame. The packets on the ISL link contain a standard Ethernet, FDDI, or Token Ring frame and the VLAN information associated with that frame. ISL is currently supported only over Fast Ethernet links, but a single ISL link, or trunk, can carry different protocols from multiple VLANs.
Procedures for configuring ISL and Token Ring ISL (TRISL) features are provided in "Configuring Routing Between VLANs with Inter-Switch Link Encapsulation" section.
IEEE 802.10 Protocol
The IEEE 802.10 protocol provides connectivity between VLANs. Originally developed to address the growing need for security within shared LAN/MAN environments, it incorporates authentication and encryption techniques to ensure data confidentiality and integrity throughout the network. Additionally, by functioning at Layer 2, it is well suited to high-throughput, low-latency switching environments. The IEEE 802.10 protocol can run over any LAN or HDLC serial interface.
Procedures for configuring routing between VLANs with IEEE 802.10 encapsulation are provided in the "Configuring Routing Between VLANs with IEEE 802.10 Encapsulation" section.
IEEE 802.1Q Protocol
The IEEE 802.1Q protocol is used to interconnect multiple switches and routers, and for defining VLAN topologies. Cisco currently supports IEEE 802.1Q for Fast Ethernet and Gigabit Ethernet interfaces.
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Procedures for configuring routing between VLANs with IEEE 802.1Q encapsulation are provided in the "Configuring Routing Between VLANs with IEEE 802.1Q Encapsulation" section.
ATM LANE Protocol
The ATM LAN Emulation (LANE) protocol provides a way for legacy LAN users to take advantage of ATM benefits without requiring modifications to end-station hardware or software. LANE emulates a broadcast environment like IEEE 802.3 Ethernet on top of an ATM network that is a point-to-point environment.
LANE makes ATM function like a LAN. LANE allows standard LAN drivers like NDIS and ODI to be used. The virtual LAN is transparent to applications. Applications can use normal LAN functions without the underlying complexities of the ATM implementation. For example, a station can send broadcasts and multicasts, even though ATM is defined as a point-to-point technology and does not support any-to-any services.
To accomplish this, special low-level software is implemented on an ATM client workstation, called the LAN Emulation Client (LEC). The client software communicates with a central control point called a LAN Emulation Server (LES). A broadcast and unknown server (BUS) acts as a central point to distribute broadcasts and multicasts. The LAN Emulation Configuration Server (LECS) holds a database of LECs and the ELANs they belong to. The database is maintained by a network administrator.
These protocols are described in detail in the Cisco Internetworking Design Guide.
ATM LANE Fast Simple Server Replication Protocol
To improve the ATM LANE Simple Server Replication Protocol (SSRP), Cisco introduced the ATM LANE Fast Simple Server Replication Protocol (FSSRP). FSSRP differs from LANE SSRP in that all configured LANE servers of an ELAN are always active. FSSRP-enabled LANE clients have virtual circuits (VCs) established to a maximum of four LANE servers and BUSs at one time. If a single LANE server goes down, the LANE client quickly switches over to the next LANE server and BUS, resulting in no data or LE ARP table entry loss and no extraneous signalling.
The FSSRP feature improves upon SSRP such that LANE server and BUS switchover for LANE clients is immediate. With SSRP, a LANE server would go down, and depending on the network load, it may have taken considerable time for the LANE client to come back up joined to the correct LANE server and BUS. In addition to going down with SSRP, the LANE client would do the following:
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FSSRP was designed to alleviate these problems with the LANE client. With FSSRP, each LANE client is simultaneously joined to up to four LANE servers and BUSs. The concept of the master LANE server and BUS is maintained; the LANE client uses the master LANE server when it needs LANE server BUS services. However, the difference between SSRP and FSSRP is that if and when the master LANE server goes down, the LANE client is already connected to multiple backup LANE servers and BUSs. The LANE client simply uses the next backup LANE server and BUS as the master LANE server and BUS.
VLAN Interoperability
Cisco IOS features bring added benefits to the VLAN technology. Enhancements to ISL, IEEE 802.10, and ATM LANE implementations enable routing of all major protocols between VLANs. These enhancements allow users to create more robust networks incorporating VLAN configurations by providing communications capabilities between VLANs.
Inter-VLAN Communications
The Cisco IOS supports full routing of several protocols over ISL and ATM LANE VLANs. IP, Novell IPX, and AppleTalk routing are supported over IEEE 802.10 VLANs. Standard routing attributes such as network advertisements, secondaries, and help addresses are applicable, and VLAN routing is fast switched. Table 39 shows protocols supported for each VLAN encapsulation format and corresponding Cisco IOS software releases.
VLAN Translation
VLAN translation refers to the ability of the Cisco IOS software to translate between different VLANs or between VLAN and non-VLAN encapsulating interfaces at Layer 2. Translation is typically used for selective inter-VLAN switching of nonroutable protocols and to extend a single VLAN topology across hybrid switching environments. It is also possible to bridge VLANs on the main interface; the VLAN encapsulating header is preserved. Topology changes in one VLAN domain do not affect a different VLAN.
Designing Switched VLANs
By the time you are ready to configure routing between VLANs, you will have already defined them through the switches in your network. Issues related to network design and VLAN definition should be addressed during your network design. Refer to the Cisco Internetworking Design Guide and appropriate switch documentation for information on these topics:
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How to Configure Routing Between VLANS
This section contains the following configuration procedure groups:
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Configuring a VLAN Range
Using the VLAN Range feature, you can group VLAN subinterfaces together so that any command entered in a group applies to every subinterface within the group. This capability simplifies configurations and reduces command parsing.
Restrictions
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Supported Platforms
For Cisco IOS Release 12.2(13)T, the following platforms are supported:
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Benefits
The VLAN Range feature provides the following benefits:
Simultaneous Configurations
Identical commands can be entered once for a range of subinterfaces, rather than being entered separately for each subinterface.
Overlapping Range Configurations
Overlapping ranges of subinterfaces can be configured.
Customized Subinterfaces
Individual subinterfaces within a range can be customized or deleted.
Configuring a Range of VLAN Subinterfaces
Use the following commands to configure a range of VLAN subinterfaces.
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Configuring Routing Between VLANs with Inter-Switch Link Encapsulation
This section describes the Inter-Switch Link (ISL) protocol and provides guidelines for configuring ISL and Token Ring ISL (TRISL) features. This section contains the following:
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Frame Tagging in ISL
ISL is a Cisco protocol for interconnecting multiple switches and maintaining VLAN information as traffic goes between switches. ISL provides VLAN capabilities while maintaining full wire speed performance on Fast Ethernet links in full- or half-duplex mode. ISL operates in a point-to-point environment and will support up to 1000 VLANs. You can define virtually as many logical networks as are necessary for your environment.
With ISL, an Ethernet frame is encapsulated with a header that transports VLAN IDs between switches and routers. A 26-byte header that contains a 10-bit VLAN ID is propounded to the Ethernet frame.
A VLAN ID is added to the frame only when the frame is prepended for a nonlocal network. Figure 78 shows VLAN packets traversing the shared backbone. Each VLAN packet carries the VLAN ID within the packet header.
Figure 78 VLAN Packets Traversing the Shared Backbone
You can configure routing between any number of VLANs in your network. This section documents the configuration tasks for each protocol supported with ISL encapsulation. The basic process is the same, regardless of the protocol being routed. It involves the following tasks:
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Configuring AppleTalk Routing over ISL
AppleTalk can be routed over VLAN subinterfaces using the ISL and IEEE 802.10 VLAN encapsulation protocols. The AppleTalk Routing over ISL and IEEE 802.10 Virtual LANs feature provides full-feature Cisco IOS software AppleTalk support on a per-VLAN basis, allowing standard AppleTalk capabilities to be configured on VLANs.
To route AppleTalk over ISL or IEEE 802.10 between VLANs, you need to customize the subinterface to create the environment in which it will be used. Perform the steps in the order in which they appear.
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Configuring Banyan VINES Routing over ISL
Banyan VINES can be routed over VLAN subinterfaces using the ISL encapsulation protocol. The Banyan VINES Routing over ISL Virtual LANs feature provides full-feature Cisco IOS software Banyan VINES support on a per-VLAN basis, allowing standard Banyan VINES capabilities to be configured on VLANs.
To route Banyan VINES over ISL between VLANs, you need to configure ISL encapsulation on the subinterface. Perform the steps in the following task in the order in which they appear:
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Configuring DECnet Routing over ISL
DECnet can be routed over VLAN subinterfaces using the ISL VLAN encapsulation protocols. The DECnet Routing over ISL Virtual LANs feature provides full-feature Cisco IOS software DECnet support on a per-VLAN basis, allowing standard DECnet capabilities to be configured on VLANs.
To route DECnet over ISL VLANs, you need to configure ISL encapsulation on the subinterface. Perform the steps described in the following task in the order in which they appear.
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Configuring the Hot Standby Router Protocol over ISL
The Hot Standby Router Protocol (HSRP) provides fault tolerance and enhanced routing performance for IP networks. HSRP allows Cisco IOS routers to monitor each other's operational status and very quickly assume packet forwarding responsibility in the event the current forwarding device in the HSRP group fails or is taken down for maintenance. The standby mechanism remains transparent to the attached hosts and can be deployed on any LAN type. With multiple Hot Standby groups, routers can simultaneously provide redundant backup and perform loadsharing across different IP subnets.
Figure 79 illustrates HSRP in use with ISL providing routing between several VLANs.
Figure 79 Hot Standby Router Protocol in VLAN Configurations
A separate HSRP group is configured for each VLAN subnet so that Cisco IOS router A can be the primary and forwarding router for VLANs 10 and 20. At the same time, it acts as backup for VLANs 30 and 40. Conversely, Router B acts as the primary and forwarding router for ISL VLANs 30 and 40, as well as the secondary and backup router for distributed VLAN subnets 10 and 20.
Running HSRP over ISL allows users to configure redundancy between multiple routers that are configured as front ends for VLAN IP subnets. By configuring HSRP over ISLs, users can eliminate situations in which a single point of failure causes traffic interruptions. This feature inherently provides some improvement in overall networking resilience by providing load balancing and redundancy capabilities between subnets and VLANs.
To configure HSRP over ISLs between VLANs, you need to create the environment in which it will be used. Perform the tasks described in the following sections in the order in which they appear.
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Configuring IP Routing over TRISL
The IP routing over TRISL VLANs feature extends IP routing capabilities to include support for routing IP frame types in VLAN configurations.
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Configuring IPX Routing on 802.10 VLANs over ISL
The IPX Encapsulation for 802.10 VLAN feature provides configurable IPX (Novell-FDDI, SAP, SNAP) encapsulation over 802.10 VLAN on router FDDI interfaces to connect the Catalyst 5000 VLAN switch. This feature extends Novell NetWare routing capabilities to include support for routing all standard IPX encapsulations for Ethernet frame types in VLAN configurations. Users with Novell NetWare environments can now configure any one of the three IPX Ethernet encapsulations to be routed using Secure Data Exchange (SDE) encapsulation across VLAN boundaries. IPX encapsulation options now supported for VLAN traffic include the following:
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NetWare users can now configure consolidated VLAN routing over a single VLAN trunking FDDI interface. Not all IPX encapsulations are currently supported for SDE VLAN. The IPX interior encapsulation support can be achieved by messaging the IPX header before encapsulating in the SDE format. Fast switching will also support all IPX interior encapsulations on non-MCI platforms (for example non-AGS+ and non-7000). With configurable Ethernet encapsulation protocols, users have the flexibility of using VLANs regardless of their NetWare Ethernet encapsulation. Configuring Novell IPX encapsulations on a per-VLAN basis facilitates migration between versions of Netware. NetWare traffic can now be routed across VLAN boundaries with standard encapsulation options (arpa, sap, and snap) previously unavailable. Encapsulation types and corresponding framing types are described in the "Configuring Novell IPX" chapter of the Cisco IOS AppleTalk and Novell IPX Configuration Guide.
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To configure Cisco IOS software on a router with connected VLANs to exchange different IPX framing protocols, perform the steps described in the following task in the order in which they are appear.
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Configuring IPX Routing over TRISL
The IPX Routing over ISL VLANs feature extends Novell NetWare routing capabilities to include support for routing all standard IPX encapsulations for Ethernet frame types in VLAN configurations. Users with Novell NetWare environments can configure either SAP or SNAP encapsulations to be routed using the TRISL encapsulation across VLAN boundaries. The SAP (Novell Ethernet_802.2) IPX encapsulation is supported for VLAN traffic.
NetWare users can now configure consolidated VLAN routing over a single VLAN trunking interface. With configurable Ethernet encapsulation protocols, users have the flexibility of using VLANs regardless of their NetWare Ethernet encapsulation. Configuring Novell IPX encapsulations on a per-VLAN basis facilitates migration between versions of Netware. NetWare traffic can now be routed across VLAN boundaries with standard encapsulation options (sap and snap) previously unavailable. Encapsulation types and corresponding framing types are described in the "Configuring Novell IPX" chapter of the Cisco IOS AppleTalk and Novell IPX Configuration Guide.
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To configure Cisco IOS software to exchange different IPX framing protocols on a router with connected VLANs, perform the steps in the following task in the order in which they are appear.
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Configuring VIP Distributed Switching over ISL
With the introduction of the VIP distributed ISL feature, ISL encapsulated IP packets can be switched on Versatile Interface Processor (VIP) controllers installed on Cisco 7500 series routers.
The second generation VIP2 provides distributed switching of IP encapsulated in ISL in VLAN configurations. Where an aggregation route performs inter-VLAN routing for multiple VLANs, traffic can be switched autonomously on-card or between cards rather than through the central Route Switch Processor (RSP). Figure 80 shows the VIP distributed architecture of the Cisco 7500 series router.
Figure 80 Cisco 7500 Distributed Architecture
This distributed architecture allows incremental capacity increases by installation of additional VIP cards. Using VIP cards for switching the majority of IP VLAN traffic in multiprotocol environments substantially increases routing performance for the other protocols because the RSP offloads IP and can then be dedicated to switching the non-IP protocols.
VIP distributed switching offloads switching of ISL VLAN IP traffic to the VIP card, removing involvement from the main CPU. Offloading ISL traffic to the VIP card substantially improves networking performance. Because you can install multiple VIP cards in a router, VLAN routing capacity is increased linearly according to the number of VIP cards installed in the router.
To configure distributed switching on the VIP, you must first configure the router for IP routing. Perform the tasks described in the following task in the order in which they appear.
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Configuring XNS Routing over ISL
XNS can be routed over VLAN subinterfaces using the ISL VLAN encapsulation protocol. The XNS Routing over ISL Virtual LANs feature provides full-feature Cisco IOS software XNS support on a per-VLAN basis, allowing standard XNS capabilities to be configured on VLANs.
To route XNS over ISL VLANs, you need to configure ISL encapsulation on the subinterface. Perform the steps described in the following task in the order in which they appear.
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Configuring CLNS Routing over ISL
CLNS can be routed over VLAN subinterfaces using the ISL VLAN encapsulation protocol. The CLNS Routing over ISL Virtual LANs feature provides full-feature Cisco IOS software CLNS support on a per-VLAN basis, allowing standard CLNS capabilities to be configured on VLANs.
To route CLNS over ISL VLANs, you need to configure ISL encapsulation on the subinterface. Perform the steps described in the following task in the order in which they appear.
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Configuring IS-IS Routing over ISL
IS-IS routing can be enabled over VLAN subinterfaces using the ISL VLAN encapsulation protocol. The IS-IS Routing over ISL Virtual LANs feature provides full-feature Cisco IOS software IS-IS support on a per-VLAN basis, allowing standard IS-IS capabilities to be configured on VLANs.
To enable IS-IS over ISL VLANs, you need to configure ISL encapsulation on the subinterface. Perform the steps described in the following task in the order in which they appear.
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Configuring Routing Between VLANs with IEEE 802.10 Encapsulation
This section describes the required and optional tasks for configuring routing between VLANs with IEEE 802.10 encapsulation.
HDLC serial links can be used as VLAN trunks in IEEE 802.10 VLANs to extend a virtual topology beyond a LAN backbone.
AppleTalk can be routed over VLAN subinterfaces using the ISL or IEEE 802.10 VLANs feature that provides full-feature Cisco IOS software AppleTalk support on a per-VLAN basis, allowing standard AppleTalk capabilities to be configured on VLANs.
AppleTalk users can now configure consolidated VLAN routing over a single VLAN trunking interface. Prior to introduction of this feature, AppleTalk could be routed only on the main interface on a LAN port. If AppleTalk routing was disabled on the main interface or if the main interface was shut down, the entire physical interface would stop routing any AppleTalk packets. With this feature enabled, AppleTalk routing on subinterfaces will be unaffected by changes in the main interface with the main interface in the "no-shut" state.
To route AppleTalk over IEEE 802.10 between VLANs, create the environment in which it will be used by customizing the subinterface and perform the tasks described in the following steps in the order in which they appear.
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Configuring Routing Between VLANs with IEEE 802.1Q Encapsulation
This section describes the required and optional tasks for configuring routing between VLANs with IEEE 802.1Q encapsulation. The IEEE 802.1Q protocol is used to interconnect multiple switches and routers, and for defining VLAN topologies.
Prerequisites
Configuring routing between VLANs with IEEE 802.1Q encapsulation assumes the presence of a single spanning tree and of an explicit tagging scheme with one-level tagging.
You can configure routing between any number of VLANs in your network.
Restrictions
The IEEE 802.1Q standard is extremely restrictive to untagged frames. The standard provides only a per-port VLANs solution for untagged frames. For example, assigning untagged frames to VLANs takes into consideration only the port from which they have been received. Each port has a parameter called a permanent virtual identification (Native VLAN) that specifies the VLAN assigned to receive untagged frames.
The main characteristics of the IEEE 802.1Q are that it assigns frames to VLANs by filtering and that the standard assumes the presence of a single spanning tree and of an explicit tagging scheme with one-level tagging.
This section contains the configuration tasks for each protocol supported with IEEE 802.1Q encapsulation. The basic process is the same, regardless of the protocol being routed. It involves the following tasks:
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To configure IEEE 802.1Q on your network, perform the following tasks. One of the following tasks is required depending on the protocol being used.
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The following tasks are optional. Perform the following tasks to connect a network of hosts over a simple bridging-access device to a remote access concentrator bridge between IEEE 802.1Q VLANs. The following sections contain configuration tasks for the Integrated Routing and Bridging, Transparent Bridging, and PVST+ Between VLANs with IEEE 802.1Q Encapsulation:
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Configuring AppleTalk Routing over IEEE 802.1Q
AppleTalk can be routed over virtual LAN (VLAN) subinterfaces using the IEEE 802.1Q VLAN encapsulation protocol. AppleTalk Routing provides full-feature Cisco IOS software AppleTalk support on a per-VLAN basis, allowing standard AppleTalk capabilities to be configured on VLANs.
To route AppleTalk over IEEE 802.1Q between VLANs, you need to customize the subinterface to create the environment in which it will be used. Perform the steps in the order in which they appear.
Use the following task to enable AppleTalk routing on IEEE 802.1Q interfaces.
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Configuring IP Routing over IEEE 802.1Q
IP routing over IEEE 802.1Q extends IP routing capabilities to include support for routing IP frame types in VLAN configurations using the IEEE 802.1Q encapsulation.
To route IP over IEEE 802.1Q between VLANs, you need to customize the subinterface to create the environment in which it will be used. Perform the tasks described in the following sections in the order in which they appear.
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Once you have IP routing enabled on the router, you can customize the characteristics to suit your environment. If necessary, refer to the IP configuration chapters in the Cisco IOS IP Routing Configuration Guide for guidelines on configuring IP.
Configuring IPX Routing over IEEE 802.1Q
IPX routing over IEEE 802.1Q VLANs extends Novell NetWare routing capabilities to include support for routing Novell Ethernet_802.3 encapsulation frame types in VLAN configurations. Users with Novell NetWare environments can configure Novell Ethernet_802.3 encapsulation frames to be routed using IEEE 802.1Q encapsulation across VLAN boundaries.
To configure Cisco IOS software on a router with connected VLANs to exchange IPX Novell Ethernet_802.3 encapsulated frames, perform the steps described in the following task in the order in which they appear.
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Configuring a VLAN for a Bridge Group with Default VLAN1
Use the following task to configure a VLAN associated with a bridge group with a default native VLAN.
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Configuring a VLAN for a Bridge Group as a Native VLAN
Use the following task to configure a VLAN associated to a bridge group as a native VLAN.
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Configuring IEEE 802.1Q-in-Q VLAN Tag Termination
Encapsulating IEEE 802.1Q VLAN tags within 802.1Q enables service providers to use a single VLAN to support customers who have multiple VLANs. The IEEE 802.1Q-in-Q VLAN Tag Termination feature on the subinterface level preserves VLAN IDs and keeps traffic in different customer VLANs segregated.
Prerequisites
You must have checked Feature Navigator to verify that your Cisco device and software image support this feature.
You must be connected to an Ethernet device that supports double VLAN tag imposition/disposition or switching.
Restrictions
The following restrictions apply to the Cisco 10000 series Internet router:
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IEEE 802.1Q-in-Q VLAN Tag Termination on Subinterfaces
IEEE 802.1Q-in-Q VLAN Tag Termination simply adds another layer of IEEE 802.1Q tag (called "metro tag" or "PE-VLAN") to the 802.1Q tagged packets that enter the network. The purpose is to expand the VLAN space by tagging the tagged packets, thus producing a "double-tagged" frame. The expanded VLAN space allows the service provider to provide certain services, such as Internet access on specific VLANs for specific customers, and yet still allows the service provider to provide other types of services for their other customers on other VLANs.
Generally the service provider's customers require a range of VLANs to handle multiple applications. Service providers can allow their customers to use this feature to safely assign their own VLAN IDs on subinterfaces because these subinterface VLAN IDs are encapsulated within a service-provider designated VLAN ID for that customer. Therefore there is no overlap of VLAN IDs among customers, nor does traffic from different customers become mixed. The double-tagged frame is "terminated" or assigned on a subinterface with an expanded encapsulation dot1q command that specifies the two VLAN ID tags (outer VLAN ID and inner VLAN ID) terminated on the subinterface. See Figure 81.
IEEE 802.1Q-in-Q VLAN Tag Termination is generally supported on whichever Cisco IOS features or protocols are supported on the subinterface; the exception is that Cisco 10000 series Internet router only supports PPPoE. For example if you can run PPPoE on the subinterface, you can configure a double-tagged frame for PPPoE. The only restriction is whether you assign ambiguous or unambiguous subinterfaces for the inner VLAN ID. See the "Unambiguous and Ambiguous Subinterfaces" section.
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The primary benefit for the service provider is reduced number of VLANs supported for the same number of customers. Other benefits of this feature include:
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The Q-in-Q VLAN tag termination feature is simpler than the IEEE 802.1Q tunneling feature deployed for the Catalyst 6500 series switches or the Catalyst 3550 and Catalyst 3750 switches. Whereas switches require IEEE 802.1Q tunnels on interfaces to carry double-tagged traffic, routers need only encapsulate Q-in-Q VLAN tags within another level of 802.1Q tags in order for the packets to arrive at the correct destination as shown in Figure 81.
Figure 81 Untagged, 802.1Q-Tagged, and Double-Tagged Ethernet Frames
Cisco 10000 Series Internet Router Application
For the emerging broadband Ethernet-based DSLAM market, the Cisco 10000 series Internet router supports Q-in-Q encapsulation. With the Ethernet-based DSLAM model shown in Figure 82, customers typically get their own VLAN and all these VLANs are aggregated on a DSLAM.
Figure 82
Broadband Ethernet-based DSLAM Model of Q-in-Q VLANs
VLAN aggregation on a DSLAM will result in a lot of aggregate VLANs that at some point need to be terminated on the broadband remote access servers (BRAS). Although the model could connect the DSLAMs directly to the BRAS, a more common model uses the existing Ethernet-switched network where each DSLAM VLAN ID is tagged with a second tag (Q-in-Q) as it connects into the Ethernet-switched network.
The only model that is supported is PPPoE over Q-in-Q (PPPoEoQinQ). This can either be a PPP terminated session or as a L2TP LAC session. No IP over Q-in-Q is supported.
The Cisco 10000 series Internet router already supports plain PPPoE and PPP over 802.1Q encapsulation. Supporting PPP over Q-in-Q encapsulation is new. PPP over Q-in-Q encapsulation processing is an extension to 802.1q encapsulation processing. A Q-in-Q frame looks like a VLAN 802.1Q frame, only it has two 802.1Q tags instead of one. See Figure 81.
PPP over Q-in-Q encapsulation supports configurable outer tag Ethertype. The configurable Ethertype field values are 0x8100 (default), 0x9100, and 0x9200. See Figure 83.
Figure 83
Supported Configurable Ethertype Field Values
Security ACL Application on the Cisco 10000 Series Internet Router
The IEEE 802.1Q-in-Q VLAN Tag Termination feature provides limited security access control list (ACL) support for the Cisco 10000 series Internet router.
If you apply an ACL to PPPoE traffic on a Q-in-Q subinterface in a VLAN, apply the ACL directly on the PPPoE session, using virtual access interfaces (VAIs) or RADIUS attribute 11 or 242.
You can apply ACLs to virtual access interfaces by configuring them under virtual template interfaces. You can also configure ACLs by using RADIUS attribute 11 or 242. When you use attribute 242, a maximum of 30,000 sessions can have ACLs.
ACLs that are applied to the VLAN Q-in-Q subinterface have no effect and are silently ignored. In the following example, ACL 1 that is applied to the VLAN Q-in-Q subinterface level will be ignored:
Router(config)# interface FastEthernet3/0/0.100Router(config-subif)# encapsulation dot1q 100 second-dot1q 200Router(config-subif)# ip access-group 1Unambiguous and Ambiguous Subinterfaces
The encapsulation dot1q command is used to configure Q-in-Q termination on a subinterface. The command accepts an Outer VLAN ID and one or more Inner VLAN IDs. The outer VLAN ID always has a specific value, while inner VLAN ID can either be a specific value or a range of values.
A subinterface that is configured with a single Inner VLAN ID is called an unambiguous Q-in-Q subinterface. In the following example, Q-in-Q traffic with an Outer VLAN ID of 101 and an Inner VLAN ID of 1001 is mapped to the Gigabit Ethernet 1/0.100 subinterface:
Router(config)# interface gigabitEehernet1/0.100Router(config-subif)# encapsulation dot1q 101 second-dot1q 1001A subinterface that is configured with multiple Inner VLAN IDs is called an ambiguous Q-in-Q subinterface. By allowing multiple Inner VLAN IDs to be grouped together, ambiguous Q-in-Q subinterfaces allow for a smaller configuration, improved memory usage and better scalability.
In the following example, Q-in-Q traffic with an Outer VLAN ID of 101 and Inner VLAN IDs anywhere in the 2001-2100 and 3001-3100 range is mapped to the Gigabit Ethernet 1/0.101 subinterface.:
Router(config)# interface gigabitethernet1/0.101Router(config-subif)# encapsulation dot1q 101 second-dot1q 2001-2100,3001-3100Ambiguous subinterfaces can also use the any keyword to specify the inner VLAN ID.
See the "Monitoring and Maintaining VLAN Subinterfaces" section for an example of how VLAN IDs are assigned to subinterfaces, and for a detailed example of how the any keyword is used on ambiguous subinterfaces.
Only PPPoE is supported on ambiguous subinterfaces. Standard IP routing is not supported on ambiguous subinterfaces.
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Perform these tasks to configure the main interface used for the Q-in-Q double tagging and to configure the subinterfaces.
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Prerequisites
For the Cisco 10000 series Internet router:
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The first task is optional. A step in this task shows you how to configure the EtherType field to be 0x9100 for the outer VLAN tag, if that is required.
After the subinterface is defined, the 802.1Q encapsulation is configured to use the double tagging.
Configuring EtherType Field for Outer VLAN Tag Termination
To configure the EtherType field for Outer VLAN Tag Termination, use the following steps. This task is optional.
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Configuring the Q-in-Q Subinterface
Use the following steps to configure Q-in-Q subinterfaces. This task is required.
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Verifying the IEEE 802.1Q-in-Q VLAN Tag Termination
Perform this optional task to verify the configuration of the IEEE 802.1Q-in-Q VLAN Tag Termination feature.
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Step 1
Enables privileged EXEC mode. Enter your password if prompted.
Router> enableStep 2
Use this command to show the currently running configuration on the device. You can use delimiting characters to display only the relevant parts of the configuration.
The following shows the currently running configuration on a Cisco 7300 series router:
Router# show running-config...interface FastEthernet0/0.201encapsulation dot1Q 201ip address 10.7.7.5 255.255.255.252!interface FastEthernet0/0.401encapsulation dot1Q 401ip address 10.7.7.13 255.255.255.252!interface FastEthernet0/0.201999encapsulation dot1Q 201 second-dot1q anypppoe enable!interface FastEthernet0/0.2012001encapsulation dot1Q 201 second-dot1q 2001ip address 10.8.8.9 255.255.255.252!interface FastEthernet0/0.2012002encapsulation dot1Q 201 second-dot1q 2002ip address 10.8.8.13 255.255.255.252!interface FastEthernet0/0.4019999encapsulation dot1Q 401 second-dot1q 100-900,1001-2000pppoe enable!interface GigabitEthernet5/0.101encapsulation dot1Q 101ip address 10.7.7.1 255.255.255.252!interface GigabitEthernet5/0.301encapsulation dot1Q 301ip address 10.7.7.9 255.255.255.252!interface GigabitEthernet5/0.301999encapsulation dot1Q 301 second-dot1q anypppoe enable!interface GigabitEthernet5/0.1011001encapsulation dot1Q 101 second-dot1q 1001ip address 10.8.8.1 255.255.255.252!interface GigabitEthernet5/0.1011002encapsulation dot1Q 101 second-dot1q 1002ip address 10.8.8.5 255.255.255.252!interface GigabitEthernet5/0.1019999encapsulation dot1Q 101 second-dot1q 1-1000,1003-2000pppoe enable...The following shows the currently running configuration on a Cisco 10000 series Internet router:
Router# show running-config...interface FastEthernet1/0/0.201encapsulation dot1Q 201ip address 10.7.7.5 255.255.255.252!interface FastEthernet1/0/0.401encapsulation dot1Q 401ip address 10.7.7.13 255.255.255.252!interface FastEthernet1/0/0.201999encapsulation dot1Q 201 second-dot1q anypppoe enable!interface FastEthernet1/0/0.4019999encapsulation dot1Q 401 second-dot1q 100-900,1001-2000pppoe enable!interface GigabitEthernet5/0/0.101encapsulation dot1Q 101ip address 10.7.7.1 255.255.255.252!interface GigabitEthernet5/0/0.301encapsulation dot1Q 301ip address 10.7.7.9 255.255.255.252!interface GigabitEthernet5/0/0.301999encapsulation dot1Q 301 second-dot1q anypppoe enable!interface GigabitEthernet5/0/0.1019999encapsulation dot1Q 101 second-dot1q 1-1000,1003-2000pppoe enable...Step 3
Use this command to show the statistics for all the 802.1Q VLAN IDs. In this example, only the outer VLAN ID is displayed.
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Router# show vlans dot1qTotal statistics for 802.1Q VLAN 1:441 packets, 85825 bytes input1028 packets, 69082 bytes outputTotal statistics for 802.1Q VLAN 101:5173 packets, 510384 bytes input3042 packets, 369567 bytes outputTotal statistics for 802.1Q VLAN 201:1012 packets, 119254 bytes input1018 packets, 120393 bytes outputTotal statistics for 802.1Q VLAN 301:3163 packets, 265272 bytes input1011 packets, 120750 bytes outputTotal statistics for 802.1Q VLAN 401:1012 packets, 119254 bytes input1010 packets, 119108 bytes output
Monitoring and Maintaining VLAN Subinterfaces
Use the following task to determine whether a VLAN is a native VLAN.
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Example
The following is sample output from the show vlans command indicating a native VLAN and a bridged group:
Router# show vlansVirtual LAN ID: 1 (IEEE 802.1Q Encapsulation)vLAN Trunk Interface: FastEthernet1/0/2This is configured as native Vlan for the following interface(s) :FastEthernet1/0/2Protocols Configured: Address: Received: Transmitted:Virtual LAN ID: 100 (IEEE 802.1Q Encapsulation)vLAN Trunk Interface: FastEthernet1/0/2.1Protocols Configured: Address: Received: Transmitted:Bridging Bridge Group 1 0 0The following is sample output from the show vlans command that shows the traffic count on Fast Ethernet subinterfaces:
Router# show vlansVirtual LAN ID: 2 (IEEE 802.1Q Encapsulation)vLAN Trunk Interface: FastEthernet5/0.1Protocols Configured: Address: Received: Transmitted:IP 172.16.0.3 16 92129Virtual LAN ID: 3 (IEEE 802.1Q Encapsulation)vLAN Trunk Interface: Ethernet6/0/1.1Protocols Configured: Address: Received: Transmitted:IP 172.20.0.3 1558 1521Virtual LAN ID: 4 (Inter Switch Link Encapsulation)vLAN Trunk Interface: FastEthernet5/0.2Protocols Configured: Address: Received: Transmitted:IP 172.30.0.3 0 7Configuration Examples for Configuring Routing Between VLANs
This section provides the following configuration example:
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Single Range Configuration: Example
The following example configures the Fast Ethernet subinterfaces within the range 5/1.1 and 5/1.4 and applies the following VLAN IDs to those subinterfaces:
Fast Ethernet5/1.1 = VLAN ID 301 (vlan-id)
Fast Ethernet5/1.2 = VLAN ID 302 (vlan-id = 301 + 2 - 1 = 302)
Fast Ethernet5/1.3 = VLAN ID 303 (vlan-id = 301 + 3 - 1 = 303)
Fast Ethernet5/1.4 = VLAN ID 304 (vlan-id = 301 + 4 - 1 = 304)
Router(config)# interface range fastethernet5/1.1 - fastethernet5/1.4Router(config-if)# encapsulation dot1Q 301Router(config-if)# no shutdownRouter(config-if)#*Oct 6 08:24:35: %LINK-3-UPDOWN: Interface FastEthernet5/1.1, changed state to up*Oct 6 08:24:35: %LINK-3-UPDOWN: Interface FastEthernet5/1.2, changed state to up*Oct 6 08:24:35: %LINK-3-UPDOWN: Interface FastEthernet5/1.3, changed state to up*Oct 6 08:24:35: %LINK-3-UPDOWN: Interface FastEthernet5/1.4, changed state to up*Oct 6 08:24:36: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet5/1.1, changed state to up*Oct 6 08:24:36: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet5/1.2, changed state to up*Oct 6 08:24:36: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet5/1.3, changed state to up*Oct 6 08:24:36: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet5/1.4, changed state to upISL Encapsulation Configuration: Examples
This section provides the following configuration examples for each of the protocols described in this chapter:
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AppleTalk Routing over ISL Configuration: Example
The configuration example illustrated in Figure 84 shows AppleTalk being routed between different ISL and IEEE 802.10 VLAN encapsulating subinterfaces.
Figure 84 Routing AppleTalk over VLAN Encapsulations
As shown in Figure 84, AppleTalk traffic is routed to and from switched VLAN domains 3, 4, 100, and 200 to any other AppleTalk routing interface. This example shows a sample configuration file for the Cisco 7500 series router with the commands entered to configure the network shown in Figure 84.
Cisco 7500 Router Configuration
!appletalk routinginterface Fddi 1/0.100encapsulation sde 100appletalk cable-range 100-100 100.2appletalk zone 100!interface Fddi 1/0.200encapsulation sde 200appletalk cable-range 200-200 200.2appletalk zone 200!interface FastEthernet 2/0.3encapsulation isl 3appletalk cable-range 3-3 3.2appletalk zone 3!interface FastEthernet 2/0.4encapsulation isl 4appletalk cable-range 4-4 4.2appletalk zone 4!Banyan VINES Routing over ISL Configuration: Example
To configure routing of the Banyan VINES protocol over ISL trunks, you need to define ISL as the encapsulation type. This example shows Banyan VINES configured to be routed over an ISL trunk:
vines routinginterface fastethernet 0.1encapsulation isl 100vines metric 2DECnet Routing over ISL Configuration: Example
To configure routing the DECnet protocol over ISL trunks, you need to define ISL as the encapsulation type. This example shows DECnet configured to be routed over an ISL trunk:
decnet routing 2.1interface fastethernet 1/0.1encapsulation isl 200decnet cost 4HSRP over ISL Configuration: Example
The configuration example shown in Figure 85 shows HSRP being used on two VLAN routers sending traffic to and from ISL VLANs through a Catalyst 5000 switch. Each router forwards its own traffic and acts as a standby for the other.
Figure 85 Hot Standby Router Protocol Sample Configuration
The topology shown in Figure 85 shows a Catalyst VLAN switch supporting Fast Ethernet connections to two routers running HSRP. Both routers are configured to route HSRP over ISLs.
The standby conditions are determined by the standby commands used in the configuration. Traffic from Host 1 is forwarded through Router A. Because the priority for the group is higher, Router A is the active router for Host 1. Because the priority for the group serviced by Host 2 is higher in Router B, traffic from Host 2 is forwarded through Router B, making Router B its active router.
In the configuration shown in Figure 85, if the active router becomes unavailable, the standby router assumes active status for the additional traffic and automatically routes the traffic normally handled by the router that has become unavailable.
Host 1 Configuration
interface Ethernet 1/2ip address 10.1.1.25 255.255.255.0ip route 0.0.0.0 0.0.0.0 10.1.1.101Host 2 Configuration
interface Ethernet 1/2ip address 10.1.1.27 255.255.255.0ip route 0.0.0.0 0.0.0.0 10.1.1.102!Router A Configuration
interface FastEthernet 1/1.110encapsulation isl 110ip address 10.1.1.2 255.255.255.0standby 1 ip 10.1.1.101standby 1 preemptstandby 1 priority 105standby 2 ip 10.1.1.102standby 2 preempt!end!Router B Configuration
interface FastEthernet 1/1.110encapsulation isl 110ip address 10.1.1.3 255.255.255.0standby 1 ip 10.1.1.101standby 1 preemptstandby 2 ip 10.1.1.102standby 2 preemptstandby 2 priority 105router igrp 1!network 10.1.0.0network 10.2.0.0!VLAN Switch Configuration
set vlan 110 5/4set vlan 110 5/3set trunk 2/8 110set trunk 2/9 110IP Routing with RIF Between TrBRF VLANs: Example
Figure 86 shows IP routing with RIF between two TrBRF VLANs.
Figure 86 IP Routing with RIF Between TrBRF VLANs
The following is the configuration for the router:
interface FastEthernet4/0.1ip address 10.5.5.1 255.255.255.0encapsulation tr-isl trbrf-vlan 999 bridge-num 14multiring trcrf-vlan 200 ring 100multiring all!interface FastEthernet4/0.2ip address 10.4.4.1 255.255.255.0encapsulation tr-isl trbrf-vlan 998 bridge-num 13multiring trcrf-vlan 300 ring 101multiring allThe following is the configuration for the Catalyst 5000 switch with the Token Ring switch module in slot 5. In this configuration, the Token Ring port 102 is assigned with TrCRF VLAN 40 and the Token Ring port 103 is assigned with TrCRF VLAN 50:
#vtpset vtp domain trislset vtp mode serverset vtp v2 enable#dripset set tokenring reduction enableset tokenring distrib-crf disable#vlansset vlan 999 name trbrf type trbrf bridge 0xe stp ieeeset vlan 200 name trcrf200 type trcrf parent 999 ring 0x64 mode srbset vlan 40 name trcrf40 type trcrf parent 999 ring 0x66 mode srbset vlan 998 name trbrf type trbrf bridge 0xd stp ieeeset vlan 300 name trcrf300 type trcrf parent 998 ring 0x65 mode srbset vlan 50 name trcrf50 type trcrf parent 998 ring 0x67 mode srb#add token port to trcrf 40set vlan 40 5/1#add token port to trcrf 50set vlan 50 5/2set trunk 1/2 onIP Routing Between a TRISL VLAN and an Ethernet ISL VLAN: Example
Figure 87 shows IP routing between a TRISL VLAN and an Ethernet ISL VLAN.
Figure 87 IP Routing Between a TRISL VLAN and an Ethernet ISL VLAN
The following is the configuration for the router:
interface FastEthernet4/0.1ip address 10.5.5.1 255.255.255.0encapsulation tr-isl trbrf-vlan 999 bridge-num 14multiring trcrf-vlan 20 ring 100multiring all!interface FastEthernet4/0.2ip address 10.4.4.1 255.255.255.0encapsulation isl 12IPX Routing over ISL Configuration: Example
Figure 88 shows IPX interior encapsulations configured over ISL encapsulation in VLAN configurations. Note that three different IPX encapsulation formats are used. VLAN 20 uses SAP encapsulation, VLAN 30 uses ARPA, and VLAN 70 uses novell-ether encapsulation. Prior to the introduction of this feature, only the default encapsulation format, "novell-ether," was available for routing IPX over ISL links in VLANs.
Figure 88 Configurable IPX Encapsulations Routed over ISL in VLAN Configurations
VLAN 20 Configuration
ipx routinginterface FastEthernet 2/0no shutdowninterface FastEthernet 2/0.20encapsulation isl 20ipx network 20 encapsulation sapVLAN 30 Configuration
ipx routinginterface FastEthernet 2/0no shutdowninterface FastEthernet 2/0.30encapsulation isl 30ipx network 30 encapsulation arpaVLAN 70 Configuration
ipx routinginterface FastEthernet 3/0no shutdowninterface Fast3/0.70encapsulation isl 70ipx network 70 encapsulation novell-etherIPX Routing on FDDI Interfaces with SDE: Example
The following example enables IPX routing on FDDI interfaces 0.2 and 0.3 with SDE. On FDDI interface 0.2, the encapsulation type is SNAP. On FDDI interface 0.3, the encapsulation type is Novell's FDDI_RAW.
ipx routinginterface fddi 0.2 enc sde 2ipx network f02 encapsulation snapinterface fddi 0.3 enc sde 3ipx network f03 encapsulation novell-fddiRouting with RIF Between a TRISL VLAN and a Token Ring Interface: Example
Figure 89 shows routing with RIF between a TRISL VLAN and a Token Ring interface.
Figure 89 Routing with RIF Between a TRISL VLAN and a Token Ring Interface
The following is the configuration for the router:
source-bridge ring-group 100!interface TokenRing 3/1ip address 10.4.4.1 255.255.255.0!interface FastEthernet4/0.1ip address 10.5.5.1 255.255.255.0encapsulation tr-isl trbrf 999 bridge-num 14multiring trcrf-vlan 200 ring-group 100multiring allThe following is the configuration for the Catalyst 5000 switch with the Token Ring switch module in slot 5. In this configuration, the Token Ring port 1 is assigned to the TrCRF VLAN 40:
#vtpset vtp domain trislset vtp mode serverset vtp v2 enable#dripset set tokenring reduction enableset tokenring distrib-crf disable#vlansset vlan 999 name trbrf type trbrf bridge 0xe stp ieeeset vlan 200 name trcrf200 type trcrf parent 999 ring 0x64 mode srtset vlan 40 name trcrf40 type trcrf parent 999 ring 0x1 mode srt#add token port to trcrf 40set vlan 40 5/1set trunk 1/2 onVIP Distributed Switching over ISL Configuration: Example
Figure 90 shows a topology in which Catalyst VLAN switches are connected to routers forwarding traffic from a number of ISL VLANs. With the VIP distributed ISL capability in the Cisco 7500 series router, each VIP card can route ISL-encapsulated VLAN IP traffic. The inter-VLAN routing capacity is increased linearly by the packet-forwarding capability of each VIP card.
Figure 90 VIP Distributed ISL VLAN Traffic
In Figure 90, the VIP cards forward the traffic between ISL VLANs or any other routing interface. Traffic from any VLAN can be routed to any of the other VLANs, regardless of which VIP card receives the traffic.
These commands show the configuration for each of the VLANs shown in Figure 90:
interface FastEthernet1/0/0ip address 10.1.1.1 255.255.255.0ip route-cache distributedfull-duplexinterface FastEthernet1/0/0.1ip address 10.1.1.1 255.255.255.0encapsulation isl 1interface FastEthernet1/0/0.2ip address 10.1.2.1 255.255.255.0encapsulation isl 2interface FastEthernet1/0/0.3ip address 10.1.3.1 255.255.255.0encapsulation isl 3interface FastEthernet1/1/0ip route-cache distributedfull-duplexinterface FastEthernet1/1/0.1ip address 172.16.1.1 255.255.255.0encapsulation isl 4interface Fast Ethernet 2/0/0ip address 10.1.1.1 255.255.255.0ip route-cache distributedfull-duplexinterface FastEthernet2/0/0.5ip address 10.2.1.1 255.255.255.0encapsulation isl 5interface FastEthernet2/1/0ip address 10.3.1.1 255.255.255.0ip route-cache distributedfull-duplexinterface FastEthernet2/1/0.6ip address 10.4.6.1 255.255.255.0encapsulation isl 6interface FastEthernet2/1/0.7ip address 10.4.7.1 255.255.255.0encapsulation isl 7XNS Routing over ISL Configuration: Example
To configure routing of the XNS protocol over ISL trunks, you need to define ISL as the encapsulation type. This example shows XNS configured to be routed over an ISL trunk:
xns routing 0123.4567.adcbinterface fastethernet 1/0.1encapsulation isl 100xns network 20CLNS Routing over ISL Configuration: Example
To configure routing of the CLNS protocol over ISL trunks, you need to define ISL as the encapsulation type. This example shows CLNS configured to be routed over an ISL trunk:
clns routinginterface fastethernet 1/0.1encapsulation isl 100clns enableIS-IS Routing over ISL Configuration: Example
To configure IS-IS routing over ISL trunks, you need to define ISL as the encapsulation type. This example shows IS-IS configured over an ISL trunk:
isis routing test-proc2net 49.0001.0002.aaaa.aaaa.aaaa.00interface fastethernet 2.0encapsulation isl 101clns router is-is test-proc2Routing IEEE 802.10 Configuration: Example
The configuration example shown in Figure 91 shows AppleTalk being routed between different ISL and IEEE 802.10 VLAN encapsulating subinterfaces.
Figure 91 Routing AppleTalk over VLAN encapsulations
As shown in Figure 91, AppleTalk traffic is routed to and from switched VLAN domains 3, 4, 100, and 200 to any other AppleTalk routing interface. This example shows a sample configuration file for the Cisco 7500 series router with the commands entered to configure the network shown in Figure 91.
Cisco 7500 Router Configuration
!interface Fddi 1/0.100encapsulation sde 100appletalk cable-range 100-100 100.2appletalk zone 100!interface Fddi 1/0.200encapsulation sde 200appletalk cable-range 200-200 200.2appletalk zone 200!interface FastEthernet 2/0.3encapsulation isl 3appletalk cable-range 3-3 3.2appletalk zone 3!interface FastEthernet 2/0.4encapsulation isl 4appletalk cable-range 4-4 4.2appletalk zone 4!IEEE 802.1Q Encapsulation Configuration: Examples
Configuration examples for each protocols are provided in the following sections:
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Configuring AppleTalk over IEEE 802.1Q: Example
This configuration example shows AppleTalk being routed on VLAN 100:
!appletalk routing!interface fastethernet 4/1.100encapsulation dot1q 100appletalk cable-range 100-100 100.1appletalk zone eng!Configuring IP Routing over IEEE 802.1Q: Example
This configuration example shows IP being routed on VLAN 101:
!ip routing!interface fastethernet 4/1.101encapsulation dot1q 101ip addr 10.0.0.11 255.0.0.0!Configuring IPX Routing over IEEE 802.1Q: Example
This configuration example shows IPX being routed on VLAN 102:
!ipx routing!interface fastethernet 4/1.102encapsulation dot1q 102ipx network 100!VLAN 100 for Bridge Group 1 with Default VLAN1: Example
The following example configures VLAN 100 for bridge group 1 with a default VLAN1:
interface FastEthernet 4/1.100encapsulation dot1q 1bridge-group 1VLAN 20 for Bridge Group 1 with Native VLAN: Example
The following example configures VLAN 20 for bridge group 1 as a native VLAN:
interface FastEthernet 4/1.100encapsulation dot1q 20 nativebridge-group 1VLAN ISL or IEEE 802.1Q Routing: Example
The following example configures VLAN ISL or IEEE 802.10 routing:
ipx routingappletalk routing!interface Ethernet 1ip address 10.1.1.1 255.255.255.0appletalk cable-range 1-1 1.1appletalk zone 1ipx network 10 encapsulation snap!router igrp 1network 10.1.0.0!end!#Catalyst5000!set VLAN 110 2/1set VLAN 120 2/2!set trunk 1/1 110,120# if 802.1Q, set trunk 1/1 nonegotiate 110, 120!end!ipx routingappletalk routing!interface FastEthernet 1/1.110encapsulation isl 110!if 802.1Q, encapsulation dot1Q 110ip address 10.1.1.2 255.255.255.0appletalk cable-range 1.1 1.2appletalk zone 1ipx network 110 encapsulation snap!interface FastEthernet 1/1.120encapsulation isl 120!if 802.1Q, encapsulation dot1Q 120ip address 10.2.1.2 255.255.255.0appletalk cable-range 2-2 2.2appletalk zone 2ipx network 120 encapsulation snap!router igrp 1network 10.1.0.0network 10.2.1.0.0!end!ipx routingappletalk routing!interface Ethernet 1ip address 10.2.1.3 255.255.255.0appletalk cable-range 2-2 2.3appletalk zone 2ipx network 120 encapsulation snap!router igrp 1network 10.2.0.0!endVLAN IEEE 802.1Q Bridging: Example
The following examples configures IEEE 802.1Q bridging:
interface FastEthernet4/0no ip addressno ip route-cachehalf-duplex!interface FastEthernet4/0.100encapsulation dot1Q 100no ip route-cachebridge-group 1!interface FastEthernet4/0.200encapsulation dot1Q 200 nativeno ip route-cachebridge-group 2!interface FastEthernet4/0.300encapsulation dot1Q 1no ip route-cachebridge-group 3!interface FastEthernet10/0no ip addressno ip route-cachehalf-duplex!interface FastEthernet10/0.100encapsulation dot1Q 100no ip route-cachebridge-group 1!interface Ethernet11/3no ip addressno ip route-cachebridge-group 2!interface Ethernet11/4no ip addressno ip route-cachebridge-group 3!bridge 1 protocol ieeebridge 2 protocol ieeebridge 3 protocol ieeeVLAN IEEE 802.1Q IRB: Example
The following examples configures IEEE 802.1Q integrated routing and bridging:
ip cefappletalk routingipx routing 0060.2f27.5980!bridge irb!interface TokenRing3/1no ip addressring-speed 16bridge-group 2!interface FastEthernet4/0no ip addresshalf-duplex!interface FastEthernet4/0.100encapsulation dot1Q 100bridge-group 1!interface FastEthernet4/0.200encapsulation dot1Q 200bridge-group 2!interface FastEthernet10/0ip address 10.3.1.10 255.255.255.0half-duplexappletalk cable-range 200-200 200.10appletalk zone irbipx network 200!interface Ethernet11/3no ip addressbridge-group 1!interface BVI 1ip address 10.1.1.11 255.255.255.0appletalk cable-range 100-100 100.11appletalk zone bridgingipx network 100!router ripnetwork 10.0.0.0network 10.3.0.0!bridge 1 protocol ieeebridge 1 route appletalkbridge 1 route ipbridge 1 route ipxbridge 2 protocol ieee!Configuring IEEE 802.1Q-in-Q VLAN Tag Termination: Example
Some ambiguous subinterfaces can use the any keyword for the inner VLAN ID specification. The any keyword represents any inner VLAN ID that is not explicitly configured on any other interface. In the following example, seven subinterfaces are configured with various outer and inner VLAN IDs.
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interface GigabitEthernet1/0/0.1encapsulation dot1q 100 second-dot1q 100interface GigabitEthernet1/0/0.2encapsulation dot1q 100 second-dot1q 200interface GigabitEthernet1/0/0.3encapsulation dot1q 100 second-dot1q 300-400,500-600interface GigabitEthernet1/0/0.4encapsulation dot1q 100 second-dot1q anyinterface GigabitEthernet1/0/0.5encapsulation dot1q 200 second-dot1q 50interface GigabitEthernet1/0/0.6encapsulation dot1q 200 second-dot1q 1000-2000,3000-4000interface GigabitEthernet1/0/0.7encapsulation dot1q 200 second-dot1q anyTable 40 shows which subinterfaces are mapped to different values of the outer and inner VLAN ID on Q-in-Q frames that come in on Gigabit Ethernet interface 1/0/0.
A new subinterface is now configured:
interface GigabitEthernet1/0/0.8encapsulation dot1q 200 second-dot1q 200-600,900-999Table 41 shows the changes made to the table for the outer VLAN ID of 200. Notice that subinterface 1/0/0.7 configured with the any keyword now has new inner VLAN ID mappings.
Additional References
The following sections provide references related to configuring a VLAN range.
Related Documents
Configuring wide-area networking
Cisco IOS Wide-Area Networking Configuration Guide, Release 12.2
Commands used in configuring wide-area networking
Cisco IOS Wide-Area Networking Command Reference, Release 12.2
Configuring interface ranges
Interface Range Specification, new feature document for Cisco IOS Release 12.1(5)T
Commands using in Configuring Routing Between VLANs with IEEE 802.10 Encapsulation
Cisco IOS Release 12.4, Cisco IOS Switching Services Command Reference
Configuring AppleTalk
Cisco IOS AppleTalk and Novell IPX Configuration Guide
Commands using in Configuring Routing Between VLANs with IEEE 802.1Q Encapsulation
Cisco IOS Release 12.4, Cisco IOS Switching Services Command Reference
IP routing configuration
Cisco IOS IP Routing Configuration Guide
Interface commands: complete command syntax, command mode, defaults, usage guidelines, and examples
Cisco IOS Interface and Hardware Component Command Reference, Release 12.3T
Interface configuration examples
Cisco IOS Interface and Hardware Component Configuration Guide
Standards
MIBs
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To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:
RFCs
Technical Assistance
Feature Information for Routing Between VLANs
Table 42 lists the features in this module and provides links to specific configuration information. Only features that were introduced or modified in Cisco IOS Releases 12.0(3)S or a later release appear in the table.
Not all commands may be available in your Cisco IOS software release. For release information about a specific command, see the command reference documentation.
Cisco IOS software images are specific to a Cisco IOS software release, a feature set, and a platform. Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://www.cisco.com/go/fn. You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.
Note
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