Cisco ONS 15327 Reference Manual, Release 4.1
Chapter 10, Ethernet Operation
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Ethernet Operation

Table Of Contents

Ethernet Operation

10.1  G-Series Application

10.1.1  G-Series Example

10.1.2  802.3z Flow Control and Frame Buffering

10.1.3  Ethernet Link Integrity Support

10.1.4  Gigabit EtherChannel/802.3ad Link Aggregation

10.2  E-Series Application

10.2.1  E-Series Modes

10.2.2  E-Series 802.3z Flow Control

10.2.3  E-Series VLAN Support

10.2.4  E-Series Q-Tagging (IEEE 802.1Q)

10.2.5  E-Series Priority Queuing (IEEE 802.1Q)

10.2.6  E-Series Spanning Tree (IEEE 802.1D)

10.3  G-Series Circuit Configurations

10.3.1  G-Series Point-to-Point Ethernet Circuits

10.3.2  G-Series Manual Cross-Connects

10.4  E-Series Circuit Configurations

10.4.1  ONS 15454 and ONS 15327 Ethernet Circuit Combinations

10.4.2  E-Series Point-to-Point Ethernet Circuits

10.4.3  E-Series Shared Packet Ring Ethernet Circuits

10.4.4  E-Series Hub and Spoke Ethernet Circuit Provisioning

10.4.5  E-Series Ethernet Manual Cross-Connects

10.5  Remote Monitoring Specification Alarm Thresholds


Ethernet Operation


The Cisco ONS 15327 integrates Ethernet into a SONET time-division multiplexing (TDM) platform. The ONS 15327 supports E-Series and G-Series Ethernet cards. For Ethernet card specifications, see Chapter 2, "Card Reference." For step-by-step Ethernet card circuit configuration procedures, refer to the "Create Circuits and VT Tunnels" chapter of the Cisco ONS 15327 Procedure Guide.

Chapter topics include:

G-Series Application

E-Series Application

G-Series Circuit Configurations

E-Series Circuit Configurations

Remote Monitoring Specification Alarm Thresholds

10.1  G-Series Application

The G-Series card (G1000-2) reliably transports Ethernet and IP data across a SONET backbone. The G-Series card maps up to two Gigabit Ethernet interfaces onto a SONET transport network and provides scalable and provisionable transport bandwidth at signal levels up to STS-48c per card. The G-Series card provides line rate forwarding for all Ethernet frames (unicast, multicast, and broadcast) and can be configured to support Jumbo frames (defined as a maximum of 10,000 bytes). The G-series card incorporates features optimized for carrier-class applications such as:

High Availability (including hitless (< 50 ms) performance under software upgrades and all types of SONET/SDH equipment protection switches)

Hitless reprovisioning

Support of Gigabit Ethernet traffic at full line rate

Full TL1-based provisioning capability (refer to the Cisco ONS 15454 and Cisco ONS 15327 TL1 Command Guide for G-Series TL1 provisioning commands)

SONET style alarms support

Ethernet PM and RMON functions

Serviceability options including enhanced port states, terminal and facility loopbacks on OC-N circuit path, and J1 path trace

For additional information, including specific procedures, on the G-Series feature of terminal and facility loopbacks on the OC-N circuit path, refer to the Cisco ONS 15327 Troubleshooting Guide.

The G-Series card allows an Ethernet private line service to be provisioned and managed very much like a traditional SONET line. G-Series card applications include providing carrier-grade transparent LAN services (TLS), 100 Mbps Ethernet private line services (when combined with an external 100 Mb Ethernet switch with Gigabit uplinks), and high-availability transport for applications such as storage over MAN/WANs. The card maps a single Ethernet port to a single STS circuit. You can independently map the two ports on the G-Series card to any combination of STS-1, STS-3c, STS-6c, STS-9c, STS-12c, STS-24c, and STS-48c circuit sizes, provided the sum of the circuit sizes that terminate on a card do not exceed STS-48c.

To support a Gigabit Ethernet port at full line rate, an STS circuit with a capacity greater or equal to 1 Gbps (bidirectional 2 Gbps) is needed. An STS-24c is the minimum circuit size that can support a Gigabit Ethernet port at full line rate.

The G-Series card transmits and monitors the SONET J1 Path Trace byte in the same manner as ONS 15327 OC-N cards.


Note G-Series encapsulation is standard high-level data link control (HDLC) framing over SONET/SDH as described in RFC 1622 and RFC 2615 with the point-to-point (PPP) protocol field set to the value specified in RFC 1841.


10.1.1  G-Series Example

Figure 10-1 shows an example of a G-Series application. In this example, data traffic from the Gigabit Ethernet port of a high-end router travels across the ONS 15327 point-to-point circuit to the Gigabit Ethernet port of another high-end router.

Figure 10-1 Data Traffic on G-Series Point-To-Point Circuit

The G-Series card carries any Layer 3 protocol that can be encapsulated and transported over Gigabit Ethernet, such as IP or IPX. The data is transmitted on the Gigabit Ethernet fiber into the standard Small Form-factor Pluggable (SFP) modules on a G-Series card. The G-Series card transparently maps Ethernet frames into the SONET payload by multiplexing the payload onto a SONET OC-N card. When the SONET payload reaches the destination node, the process is reversed and the data is transmitted from the standard Cisco SFP in the destination G-Series card onto the Gigabit Ethernet fiber.

The G-Series card discards certain types of erroneous Ethernet frames rather than transport them over SONET. Erroneous Ethernet frames include corrupted frames with CRC errors and under-sized frames that do not conform to the minimum 64-byte length Ethernet standard. The G-Series card forwards valid frames unmodified over the SONET network. Information in the headers is not affected by the encapsulation and transport. For example, packets with formats that include IEEE 802.1Q information will travel through the process unaffected.

10.1.2  802.3z Flow Control and Frame Buffering

The G-Series supports 802.3z flow control and frame buffering to reduce data traffic congestion. To prevent over-subscription, 512 KB of buffer memory is available for the receive and transmit channels on each port. When the buffer memory on the Ethernet port nears capacity, the ONS 15327 uses 802.3z flow control to transmit a pause frame to the source at the opposite end of the Gigabit Ethernet connection.

The pause frame instructs the source to stop sending packets for a specific period of time. The sending station waits the requested time before sending more data. Figure 10-1 illustrates pause frames being sent and received by ONS 15327s and attached switches.

With Software R4.0 and later, the G-Series card has symmetric flow control and proposes symmetric flow control when auto-negotiating flow control with attached Ethernet devices. Symmetric flow control allows the G-Series to respond to pause frames sent from external devices and send pause frames to external devices. Prior to Software R4.0, flow control on the G-Series card was asymmetric, meaning the card sent pause frames and discarded received pause frames.

This flow-control mechanism matches the sending and receiving device throughput to that of the bandwidth of the STS circuit. For example, a router might transmit to the Gigabit Ethernet port on the G-Series. This particular data rate may occasionally exceed 622 Mbps, but the ONS 15327 circuit assigned to the G-Series port might be only STS-12c (622.08 Mbps). In this example, the ONS 15327 sends out a pause frame and requests that the router delay its transmission for a certain period of time. With flow control and a substantial per-port buffering capability, a private line service provisioned at less than full line rate capacity (STS-24c) is efficient because frame loss can be controlled to a large extent.

Release 4.1 introduces flow control threshold provisioning to the G-Series card, which allows a user to select one of three watermark (buffer size) settings: default, low latency or custom. Default is the best setting for general use and was the only setting available prior to release 4.1. Low latency is good for sub-rate applications, such as VoIP over an STS-1. For attached devices with insufficient buffering, best effort traffic or long access line lengths, set the G-Series to a higher latency.

The custom setting allows you to specify an exact buffer size threshold for Flow Ctrl Lo and Flow Ctrl Hi. The flow control high setting is the watermark for sending the "Pause On" frame to the attached Ethernet device, this frame signals the device to temporarily stop transmitting. The flow control low setting is the watermark for sending the "Pause Off" frame, which signals the device to resume transmitting.


Note External Ethernet devices with auto-negotiation that are configured to interoperate with G-Series cards running releases prior to release 4.0 do not need to change auto-negotiation settings when interoperating with G-Series cards running release 4.0 and later.



Note With a G-Series card, you can only enable flow control on a port if auto-negotiation is enabled on the device attached to that port.


10.1.3  Ethernet Link Integrity Support

The G-Series supports end-to-end Ethernet link integrity (see Figure 10-2). This capability is integral to providing an Ethernet private line service and correct operation of Layer 2 and Layer 3 protocols on the attached Ethernet devices. End-to-end Ethernet link integrity essentially means that if any part of the end-to-end path fails the entire path fails. Failure of the entire path is ensured by turning off the transmit lasers at each end of the path. The attached Ethernet devices recognize the disabled transmit laser as a loss of carrier and consequently an inactive link.

Figure 10-2 End-to-end Ethernet Link Integrity Support


Note Some network devices can be configured to ignore a loss of carrier condition. If a device configured to ignore a loss of carrier condition attaches to a G-Series card at one end, alternative techniques (such as use of Layer 2 or Layer 3 keep-alive messages) are required to route traffic around failures. The response time of such alternate techniques is typically much longer than techniques that use link state as indications of an error condition.



Note Enabling or disabling port-level flow control on the test set or other Ethernet device attached to the G-Series port can affect the transmit (Tx) laser and result in unidirectional traffic flow.


As shown in Figure 10-2, a failure at any point of the path causes the G-Series card at each end to disable its transmit (Tx) laser, which causes the devices at both ends to detect a link down. If one of the Ethernet ports is administratively disabled or set in loopback mode, the port is considered a failure for the purposes of end-to-end link integrity because the end-to-end Ethernet path is unavailable. The port failure also disables both ends of the path.

10.1.4  Gigabit EtherChannel/802.3ad Link Aggregation

The end-to-end Ethernet link integrity feature can be used in combination with Gigabit EtherChannel capability on attached devices. The combination provides an Ethernet traffic restoration scheme that has a faster response time than alternate techniques such as spanning tree rerouting, yet is more bandwidth efficient because spare bandwidth does not need to be reserved.

The G-Series supports all forms of link aggregation technologies including Gigabit EtherChannel (GEC), which is a Cisco proprietary standard, and the IEEE 802.3ad standard. The end-to-end link integrity feature of the G-Series allows a circuit to emulate an Ethernet link. This allows all flavors of Layer 2 and Layer 3 rerouting to work correctly with the G-Series. Figure 10-3 illustrates G-Series GEC support.

Figure 10-3 G-Series Gigabit EtherChannel (GEC) Support

Although the G-Series card does not actively run GEC, it supports the end-to-end GEC functionality of attached Ethernet devices. If two Ethernet devices running GEC connect through G-Series cards to an ONS 15327 network, the ONS 15327 SONET side network is transparent to the EtherChannel devices. The EtherChannel devices operate as if they are directly connected to each other. Any combination of G-Series parallel circuit sizes can be used to support GEC throughput.

GEC provides line-level active redundancy and protection (1:1) for attached Ethernet equipment. It can also bundle parallel G-Series data links together to provide more aggregated bandwidth. STP operates as if the bundled links are one link and permits GEC to utilize these multiple parallel paths. Without GEC, STP permits only a single non-blocked path. GEC can also provide G-Series card-level protection or redundancy because it can support a group of ports on different cards (or different nodes) so that if one port or card has a failure, traffic is rerouted over the other port or card.

10.2  E-Series Application

The E-Series cards (E10/100-4) incorporate Layer 2 switching, whereas the G-Series card is a straight mapper card. E-Series cards support virtual local area networks (VLANs), IEEE 802.1Q, STP, and IEEE 802.1D.

10.2.1  E-Series Modes

An E-Series card operates in one of three modes: Multicard EtherSwitch Group, Single-card EtherSwitch, or Port-mapped. Within an ONS 15327 containing multiple E-Series cards, each E-Series card can operate in any of the three separate modes. At the Ethernet card view in CTC, click the Provisioning > Ether Card tabs to reveal the card modes.


Note Port-mapped mode eliminates issues inherent in other E-Series modes and detailed in the field notice, "E-Series Ethernet Line Card Packet Forwarding Limitations."


10.2.1.1  E-Series Multicard EtherSwitch Group

Multicard EtherSwitch Group provisions two or more Ethernet cards to act as a single Layer 2 switch. It supports one STS-3c shared packet rings or three STS-1 shared packet rings. Each multicard switch may connect up to a total of STS-3c in SONET circuits. When provisioned as an add or drop node of a shared packet ring circuit, the effective bandwidth doubles, supporting STS-3c in each direction of the ring. Figure 10-4 illustrates a Multicard EtherSwitch configuration.

Figure 10-4 Multicard EtherSwitch Configuration


Caution Whenever you terminate two STS-3c multicard EtherSwitch circuits on an Ethernet card and later delete the first circuit, delete the remaining STS-3c circuit before you provision an STS-1 circuit to the card. If you attempt to create an STS-1 circuit after only deleting the first STS-3c circuit, the STS-1 circuit will not work, but no alarms will indicate this condition. To avoid this situation, delete the second STS-3c before creating an STS-1 circuit.

10.2.1.2  E-Series Single-Card EtherSwitch

Single-card EtherSwitch allows each Ethernet card to remain a single switching entity within the ONS 15327 shelf. This option allows STS-12c worth of bandwidth between two Ethernet circuit endpoints. Figure 10-5 illustrates a Single-card EtherSwitch configuration.

Figure 10-5 Single-Card EtherSwitch Configuration

10.2.1.3  Port-Mapped (Linear Mapper)

Port-mapped mode, also referred to as linear mapper, configures the E-Series card to map a specific E-Series Ethernet port to one of the STS circuits on the card (Figure 10-6). Port-mapped mode ensures Layer 1 transport has low latency for unicast, multicast, and mixed traffic. Ethernet and Fast Ethernet on the E10/100-4 card operate at line-rate speed. Ethernet frame sizes up to 1522 bytes are also supported, which allows transport of 802.1Q tagged frames. The larger maximum frame size of Q-in-Q frames, 802.1Q in 802.1Q wrapped frames, are not supported.

Figure 10-6 E-Series Mapping Ethernet Ports to SONET STS Circuits

Port-mapped mode disables Layer 2 functions supported by the E-Series in Single-card and Multicard mode, including STP, VLANs, and MAC address learning. It significantly reduces the service-affecting time for cross-connect and TCC+/TCC2 card switches.

Port-mapped mode does not support VLANs in the same manner as multicard and single-card mode. The ports of E-Series cards in multicard and single-card mode can join specific VLANs. E-Series cards in port-mapped mode do not have this Layer 2 capability and only transparently transport external VLANs over the mapped connection between ports. An E-Series card in port-mapped mode does not inspect the tag of the transported VLAN, so a VLAN range of 1 through 4096 can be transported in port-mapped mode.

Port-mapped mode also allows the creation of STS circuits between any two E-Series cards, including the E10/100-4 and, on the Cisco ONS 15454, the E1000-G and E100G-12 cards. Port-mapped mode does not allow an E-Series cards to connect to the G-Series cards or the ONS 15454 ML-Series cards.

10.2.2  E-Series 802.3z Flow Control

The E10/100-4 supports 802.3z symmetrical flow control and proposes symmetric flow control when auto-negotiating with attached Ethernet devices. For flow control to operate, both the E-Series port and the attached Ethernet device must be set to auto-negotiation (AUTO) mode. The flow-control mechanism allows the E-Series to respond to pause frames sent from external devices and send pause frames to external devices. Flow control matches the sending and receiving device throughput to that of the bandwidth of the STS circuit.


Note To enable flow control between an E-Series in port mapped mode and a SmartBits test set, manually set bit 5 of the MII register to 0 on the SmartBits test set. To enable flow control between an E-Series in port mapped mode and an Ixia test set, select Enable the flow control in the properties menu of the attached Ixia port.


10.2.3  E-Series VLAN Support

Users can provision up to 509 VLANs per network with the CTC software. Specific sets of ports define the broadcast domain for the ONS 15327. The definition of VLAN ports includes all Ethernet and packet-switched SONET port types. All VLAN IP address discovery, flooding, and forwarding is limited to these ports.

The ONS 15327 802.1Q-based VLAN mechanism provides logical isolation of subscriber LAN traffic over a common SONET transport infrastructure. Each subscriber has an Ethernet port at each site, and each subscriber is assigned to a VLAN. Although the subscriber's VLAN data flows over shared circuits, the service appears to the subscriber as a private data transport.


Note Port-mapped mode does not support VLANs.


The number of VLANs used by circuits and the total number of VLANs available for use appears in CTC on the VLAN counter (Figure 10-7).

Figure 10-7 Edit Circuit Dialog Featuring Available VLANs

10.2.4  E-Series Q-Tagging (IEEE 802.1Q)

E-Series cards in single-card and multicard mode support IEEE 802.1Q. IEEE 802.1Q allows the same physical port to host multiple 802.1Q VLANs. Each 802.1Q VLAN represents a different logical network. E-Series cards in port-mapped mode transport IEEE 802.1Q tags (Q-tags), but do not remove or add these tags.

The ONS 15327 works with Ethernet devices that support IEEE 802.1Q and those that do not support IEEE 802.1Q. If a device attached to an ONS 15327 Ethernet port does not support IEEE 802.1Q, the ONS 15327 uses Q-tags internally only. The ONS 15327 associates these Q-tags with specific ports.

With Ethernet devices that do not support IEEE 802.1Q, the ONS 15327 takes non-tagged Ethernet frames that enter the ONS network and uses a Q-tag to assign the packet to the VLAN associated with the ONS network's ingress port. The receiving ONS node removes the Q-tag when the frame leaves the ONS network (to prevent older Ethernet equipment from incorrectly identifying the 8021.Q packet as an illegal frame). The ingress and egress ports on the ONS network must be set to Untag for the removal to occur. Untag is the default setting for ONS ports. Example 1 in Figure 10-8 illustrates Q-tag use only within an ONS network.

The ONS 15327 uses the Q-tag attached by the external Ethernet devices that support IEEE 802.1Q. Packets enter the ONS network with an existing Q-tag; the ONS 15327 uses this same Q-tag to forward the packet within the ONS network and leaves the Q-tag attached when the packet leaves the ONS network. The entry and egress ports on the ONS network must be set to Tagged for this process to occur. Example 2 in Figure 10-8 illustrates the handling of packets that both enter and exit the ONS network with a Q-tag.

For more information about setting ports to Tagged and Untag, refer to the Cisco ONS 15327 Procedure Guide.


Caution ONS 15327s propagate VLANs whenever a node appears on the network view of another node, regardless of whether the nodes are in the same SONET network or connected through DCC. For example, if two ONS 15327s without DCC connectivity belong to the same login node group, VLANs propagate between the two ONS 15327s. VLAN propagation happens even though the ONS 15327s do not belong to the same SONET ring.

Figure 10-8 Q-Tag Moving through VLAN

10.2.5  E-Series Priority Queuing (IEEE 802.1Q)

Networks without priority queuing handle all packets on a first-in-first-out basis. Priority queuing reduces the impact of network congestion by mapping Ethernet traffic to different priority levels. The ONS 15327 supports priority queuing. The ONS 15327 maps the eight priorities specified in IEEE 802.1Q to two queues, low priority and high priority (Table 10-1). Q-tags carry priority queuing information through the network.

The ONS 15327 uses a "leaky bucket" algorithm to establish a weighted priority (not a strict priority). A weighted priority gives high-priority packets greater access to bandwidth, but does not totally preempt low-priority packets. During periods of network congestion, roughly 70% of bandwidth goes to the high-priority queue and the remaining 30% goes to the low-priority queue. A network that is too congested will drop packets.


Note IEEE 802.1Q was formerly IEEE 802.1P.



Note E-Series cards in port-mapped mode and G-Series cards do not support priority queuing (IEEE 8021.Q).


Table 10-1 E-Series Card User Priority Queuing

User Priority
Queue
Allocated Bandwidth

0, 1, 2, 3

Low

30%

4, 5, 6, 7

High

70%


Figure 10-9 shows the E-Series priority queuing process.

Figure 10-9 E-Series Priority Queuing Process

10.2.6  E-Series Spanning Tree (IEEE 802.1D)

The Cisco ONS 15327 operates spanning tree protocol (STP) according to IEEE 802.1D, when an Ethernet card is installed. The E-Series card supports common STPs on a per circuit basis up to a total of eight STP instances. It does not support per-VLAN STP. In single-card mode, STP can be disabled or enabled on a per circuit basis during circuit creation. Disabling STP will preserve the number of available STP instances.

STP operates over all packet-switched ports including Ethernet and OC-N ports. On Ethernet ports, STP is enabled by default but may be disabled. A user can also disable or enable STP on a circuit-by-circuit basis on unstitched Ethernet cards in a point-to-point configuration. However, turning off STP protection on a circuit-by-circuit basis means that the ONS 15327 system is not protecting the Ethernet traffic on this circuit, and the Ethernet traffic must be protected by another mechanism in the Ethernet network. On OC-N interface ports, the ONS 15327 activates STP by default, and STP cannot be disabled.

The Ethernet card can enable STP on the Ethernet ports to create redundant paths to the attached Ethernet equipment. STP connects cards so that both equipment and facilities are protected against failure.

STP detects and eliminates network loops. When STP detects multiple paths between any two network hosts, STP blocks ports until only one path exists between any two network hosts (Figure 10-10). The single path eliminates possible bridge loops. This is crucial for shared packet rings, which naturally include a loop.

Figure 10-10 STP Blocked Path

To remove loops, STP defines a tree that spans all the switches in an extended network. STP forces certain redundant data paths into a standby (blocked) state. If one network segment in the STP becomes unreachable, the STP algorithm reconfigures the STP topology and reactivates the blocked path to reestablish the link. STP operation is transparent to end stations, which do not discriminate between connections to a single LAN segment or to a switched LAN with multiple segments. The ONS 15327 supports one STP instance per circuit and a maximum of eight STP instances per ONS 15327.

The Circuit window shows forwarding spans and blocked spans on the spanning tree map (Figure 10-11).

Figure 10-11 Spanning Tree Map on the Circuit Window


Note Green represents forwarding spans and purple represents blocked (protect) spans. If you have a packet ring configuration, at least one span should be purple.



Caution Multiple circuits with STP protection enabled will incur blocking, if the circuits traverse a common card and uses the same VLAN.


Note E-Series Port-mapped mode does not support STP (IEEE 8021.D).


10.2.6.1  E-Series Multi-Instance Spanning Tree and VLANs

The ONS 15327 can operate multiple instances of STP to support VLANs in a looped topology. You can dedicate separate circuits across the SONET ring for different VLAN groups. Each circuit runs its own STP to maintain VLAN connectivity in a multiring environment.

10.2.6.2  Spanning Tree on a Circuit-by-Circuit Basis

You can also disable or enable STP on a circuit-by-circuit basis on single-card Etherswitch E-Series cards in a point-to-point configuration. This feature allows customers to mix spanning tree protected circuits with unprotected circuits on the same card. It also allows two single-card Etherswitch E-Series cards on the same node to form an intranode circuit.

10.2.6.3  E-Series Spanning Tree Parameters

Default STP parameters on Table 10-2 are appropriate for most situations. Contact the Cisco Technical Assistance before you change the default STP parameters. See the "Obtaining Technical Assistance" section on page -Boilerplate for TAC contact information.

Table 10-2 Spanning Tree Parameters 

Parameter
Description

BridgeID

ONS 15327 unique identifier that transmits the configuration bridge protocol data unit (BPDU); the bridge ID is a combination of the bridge priority and the ONS 15327 MAC address

TopoAge

Amount of time in seconds since the last topology change

TopoChanges

Number of times the STP topology has been changed since the node booted up

DesignatedRoot

Identifies the STP designated root for a particular STP instance

RootCost

Identifies the total path cost to the designated root

RootPort

Port used to reach the root

MaxAge

Maximum time that received-protocol information is retained before it is discarded

HelloTime

Time interval, in seconds, between the transmission of configuration BPDUs by a bridge that is the spanning tree root or is attempting to become the spanning tree root

HoldTime

Minimum time period, in seconds, that elapses during the transmission of configuration information on a given port

ForwardDelay

Time spent by a port in the listening state and the learning state


10.2.6.4  E-Series Spanning Tree Configuration

To view the spanning tree configuration, at the node view click the Provisioning > Etherbridge > Spanning Trees tabs (see Table 10-3).

Table 10-3 Spanning Tree Configuration

Column
Default Value
Value Range

Priority

32768

0 to 65535

Bridge max age

20 seconds

6 to 40 seconds

Bridge Hello Time

2 seconds

1 to 10 seconds

Bridge Forward Delay

15 seconds

4 to 30 seconds


10.3  G-Series Circuit Configurations

This section explains G-Series point-to-point circuits and manual cross-connects. Ethernet manual cross-connects allow you to cross connect individual Ethernet circuits to an STS channel on the ONS 15327 optical interface and also to bridge non-ONS SONET network segments.

10.3.1  G-Series Point-to-Point Ethernet Circuits

G-Series cards support point-to-point circuit configurations (Figure 10-12). Provisionable circuit sizes are STS-1, STS-3c, STS-6c, STS-9c, STS-12c, STS-24c, and STS-48c. Each Ethernet port maps to a unique STS circuit of the G-Series card.

Figure 10-12 G-Series Point-to-Point Circuit

The G-Series supports any combination of up to four circuits from the list of valid circuit sizes; however, the circuit sizes can add up to no more than 48 STSs.


Caution G-Series cards do not connect with E-Series cards.


Note The G-Series uses STS cross-connects only. No VT level cross-connects are used.


10.3.2  G-Series Manual Cross-Connects

ONS 15327s require end-to-end CTC visibility between nodes for normal provisioning of Ethernet circuits. When other vendors' equipment sits between ONS 15327s, OSI/TARP-based equipment does not allow tunneling of the ONS 15327 TCP/IP-based DCC. To circumvent a lack of continuous DCC, the Ethernet circuit must be manually cross connected to an STS channel using the non-ONS network. Manual cross-connects allows an Ethernet circuit to run from ONS node to ONS node while utilizing the non-ONS network (Figure 10-13).


Note In this chapter, "cross-connect" and "circuit" have the following meanings: Cross-connect refers to the connections that occur within a single ONS 15327 to allow a circuit to enter and exit an ONS 15327. Circuit refers to the series of connections from a traffic source (where traffic enters the ONS 15327 network) to the drop or destination (where traffic exits an ONS 15327 network).


Figure 10-13 G-Series Manual Cross-Connects

10.4  E-Series Circuit Configurations

Ethernet circuits can link ONS nodes through point-to-point (straight), shared packet ring, or hub and spoke configurations. Two nodes usually connect with a point-to-point configuration. More than two nodes usually connect with a shared packet ring configuration or a hub-and-spoke configuration. Ethernet manual cross-connects allow you to cross connect individual Ethernet circuits to an STS channel on the ONS 15327 optical interface and also to bridge non-ONS SONET network segments. For step-by-step procedures to configure E-Series circuits, refer to the Cisco ONS 15327 Procedure Guide.


Note Before making Ethernet connections, choose an STS-1, STS-3c, STS-6c, or STS-12c circuit size.



Note To make an STS-6c or STS-12c Ethernet circuit, Ethernet cards must be configured in single-card EtherSwitch or port-mapped mode. Multicard mode does not support STS-6c or STS-12c Ethernet circuits.


10.4.1  ONS 15454 and ONS 15327 Ethernet Circuit Combinations

The following table shows the Ethernet circuit combinations available in ONS 15454 E-Series cards and ONS 15327 E-Series cards.

Table 10-4 ONS 15454 and ONS 15327 Ethernet Circuit Combinations 

15327 Single-Card
15327 Port-mapped
15327 Multicard
15454 E-Series Single-Card
15454 E-Series Port-Mapped
15454 E-Series Multicard

six STS-1s

four STS-1s

three STS-1s

one STS 12c

one STS 12c

six STS-1s

two STS 3cs

two STS 3cs

one STS 3c

two STS 6cs

two STS 6cs

two STS 3cs

one STS 6c

one STS 6c

one STS 6c and two STS 3cs

one STS 6c and two STS 3cs

one STS 6c

one STS 12c

one STS 12c

one STS 6c and six STS-1s

one STS 6c and six STS-1s

four STS 3cs

four STS 3cs

two STS 3cs and six STS-1s

two STS 3cs and six STS-1s

twelve STS-1s

twelve STS-1s


10.4.2  E-Series Point-to-Point Ethernet Circuits

The ONS 15327 can set up a point-to-point (straight) Ethernet circuit as Single-card, Port-mapped or Multicard circuit. Multicard EtherSwitch limits bandwidth to STS-3c of bandwidth between two Ethernet circuit points, but allows adding nodes and cards and making a shared packet ring (see Figure 10-14).

Figure 10-14 Multicard EtherSwitch Point-to-point Circuit

Single-card EtherSwitch and Port-mapped mode allows a full STS-12c of bandwidth between two Ethernet circuit endpoints (Figure 10-15).

Figure 10-15 Single-card EtherSwitch or Port-mapped Point-to-point Circuit


Note A Port-mapped point-to-point circuit does not contain a VLAN.


10.4.3  E-Series Shared Packet Ring Ethernet Circuits

A shared packet ring allows additional nodes, besides the source and destination nodes, access to an Ethernet STS circuit. The E-Series card ports on the additional nodes can share the circuit's VLAN and bandwidth. Figure 10-16 illustrates a shared packet ring. Your network architecture may differ from the example.

Figure 10-16 Shared Packet Ring Ethernet Circuit

10.4.4  E-Series Hub and Spoke Ethernet Circuit Provisioning

The hub and spoke configuration connects point-to-point circuits (the spokes) to an aggregation point (the hub). In many cases, the hub links to a high-speed connection and the spokes are Ethernet cards. Figure 10-17 illustrates a hub and spoke ring. Your network architecture may differ from the example.

Figure 10-17 Hub And Spoke Ethernet Circuit

10.4.5  E-Series Ethernet Manual Cross-Connects

ONS 15327s require end-to-end CTC visibility between nodes for normal provisioning of Ethernet circuits. When other vendors' equipment sits between ONS 15327s, OSI/TARP-based equipment does not allow tunneling of the ONS 15327 TCP/IP-based DCC. To circumvent this lack of continuous DCC, the Ethernet circuit must be manually cross connected to an STS channel using the non-ONS network. The manual cross-connect allows an Ethernet circuit to run from ONS node to ONS node utilizing the non-ONS network.


Note In this chapter, "cross-connect" and "circuit" have the following meanings: Cross-connect refers to the connections that occur within a single ONS 15327 to allow a circuit to enter and exit an ONS 15327. Circuit refers to the series of connections from a traffic source (where traffic enters the ONS 15327 network) to the drop or destination (where traffic exits an ONS 15327 network).


10.5  Remote Monitoring Specification Alarm Thresholds

The ONS 15327 features Remote Monitoring (RMON) that allows network operators to monitor the health of the network with a Network Management System (NMS).

One of the ONS 15327's RMON MIBs is the Alarm group, which consists of the alarmTable. An NMS uses the alarmTable to find the alarm-causing thresholds for network performance. The thresholds apply to the current 15-minute interval and the current 24-hour interval. RMON monitors several variables, such as Ethernet collisions, and triggers an event when the variable crosses a threshold during that time interval. For example, if a threshold is set at 1000 collisions and 1001 collisions occur during the 15-minute interval, an event triggers. CTC allows you to provision these thresholds for Ethernet statistics.


Note Table 10-5 defines the variables you can provision in CTC. For example, to set the collision threshold, choose etherStatsCollisions from the Variable menu.


Table 10-5 Ethernet Threshold Variables (MIBs) 

Variable
Definition

iflnOctets

Total number of octets received on the interface, including framing octets

iflnUcastPkts

Total number of unicast packets delivered to an appropriate protocol

ifInMulticastPkts

Number of multicast frames received error free (not supported by E-Series)

ifInBroadcastPkts

The number of packets, delivered by this sub-layer to a higher (sub-)layer, which were addressed to a broadcast address at this sub-layer (not supported by E-Series)

ifInDiscards

The number of inbound packets which were chosen to be discarded even though no errors had been detected to prevent their being deliverable to a higher-layer protocol (not supported by E-Series)

iflnErrors

Number of inbound packets discarded because they contain errors

ifOutOctets

Total number of transmitted octets, including framing packets

ifOutUcastPkts

Total number of unicast packets requested to transmit to a single address

ifOutMulticastPkts

Number of multicast frames transmitted error free (not supported by E-Series)

ifOutBroadcastPkts

The total number of packets that higher-level protocols requested be transmitted, and which were addressed to a broadcast address at this sub-layer, including those that were discarded or not sent (not supported by E-Series)

ifOutDiscards

The number of outbound packets which were chosen to be discarded even though no errors had been detected to prevent their being transmitted (not supported by E-Series)

dot3statsAlignmentErrors

Number of frames with an alignment error, that is, the length is not an integral number of octets and the frame cannot pass the Frame Check Sequence (FCS) test

dot3StatsFCSErrors

Number of frames with framecheck errors, that is, there is an integral number of octets, but an incorrect FCS

dot3StatsSingleCollisionFrames

Number of successfully transmitted frames that had exactly one collision

dot3StatsMutlipleCollisionFrame

Number of successfully transmitted frames that had multiple collisions

dot3StatsDeferredTransmissions

Number of times the first transmission was delayed because the medium was busy

dot3StatsExcessiveCollision

Number of frames where transmissions failed because of excessive collisions

dot3StatsLateCollision

Number of times that a collision was detected later than 64 octets into the transmission (also added into collision count)

dot3StatsFrameTooLong

Number of received frames that were larger than the maximum size permitted

dot3StatsCarrierSenseErrors

The number of transmission errors on a particular interface that are not otherwise counted (not supported by E-Series)

dot3StatsSQETestErrors

A count of times that the SQE TEST ERROR message is generated by the PLS sublayer for a particular interface (not supported by E-Series)

etherStatsJabbers

Total number of Octets of data (including bad packets) received on the network

etherStatsUndersizePkts

Number of packets received with a length less than 64 octets

etherStatsFragments

Total number of packets that are not an integral number of octets or have a bad FCS, and that are less than 64 octets long

etherStatsOversizePkts

The total number of packets received that were longer than 1518 octets (excluding framing bits, but including FCS octets) and were otherwise well formed.

etherStatsOctets

The total number of octets of data (including those in bad packets) received on the network (excluding framing bits but including FCS octets)

etherStatsPkts64Octets

Total number of packets received (including error packets) that were 64 octets in length

etherStatsPkts65to127Octets

Total number of packets received (including error packets) that were 65 to 172 octets in length

etherStatsPkts128to255Octets

Total number of packets received (including error packets) that were 128 to 255 octets in length

etherStatsPkts256to511Octets

Total number of packets received (including error packets) that were 256 to 511 octets in length

etherStatsPkts512to1023Octets

Total number of packets received (including error packets) that were 512 to 1023 octets in length

etherStatsPkts1024to1518Octets

Total number of packets received (including error packets) that were 1024 to 1518 octets in length

etherStatsJabbers

Total number of packets longer than 1518 octets that were not an integral number of octets or had a bad FCS

etherStatsCollisions

Best estimate of the total number of collisions on this segment

etherStatsCollisionFrames

Best estimate of the total number of frame collisions on this segment

etherStatsCRCAlignErrors

Total number of packets with a length between 64 and 1518 octets, inclusive, that had a bad FCS or were not an integral number of octets in length

receivePauseFrames

The number of received 802.x pause frames (not supported by E-Series)

transmitPauseFrames

The number of transmitted 802.x pause frames (not supported by E-Series)

receivePktsDroppedInternalCongestion

The number of received frames dropped because of frame buffer overflow and other reasons (not supported by E-Series)

transmitPktsDroppedInternalCongestion

The number of frames dropped in the transmit direction because of frame buffer overflow and other reasons (not supported by E-Series)

txTotalPkts

Total number of transmit packets (not supported by E-Series)

rxTotalPkts

Total number of receive packets (not supported by E-Series)