Cisco 7600 Series Router SIP, SSC, and SPA Software Configuration Guide

Required Configuration Tasks

This section lists the required configuration steps to configure the 8-Port Channelized T1/E1 SPA. Some of the required configuration commands implement default values that might be appropriate for your network. If the default value is correct for your network, then you do not need to configure the command.

• Setting the Card Type
• Enabling the Interfaces on the Controller
• Verifying Controller Configuration
• Setting the IP Address
• Verifying Interface Configuration

Note To better understand the address format used to specify the physical location of the SIP, SPA, and interfaces, see the “Specifying the Interface Address on a SPA” section.

Setting the Card Type

The SPA is not functional until the card type is set. Information about the SPA is not indicated in the output of any show commands until the card type has been set. There is no default card type.

Note Mixing of interface types is not supported. All ports on a SPA must be of the same type.

To set the card type for the 8-Port Channelized T1/E1 SPA, complete these steps:

Enabling the Interfaces on the Controller

To create the interfaces for the 8-Port Channelized T1/E1 SPA, complete these steps:

Verifying Controller Configuration

Use the show controllers command to verify the controller configuration:

Setting the IP Address

To set the IP address for the 8-Port Channelized T1/E1 SPA, complete these steps:

Verifying Interface Configuration

Use the show interfaces command to verify the interface configuration:

Specifying the Interface Address on a SPA

SPA interface ports begin numbering with “0” from left to right. Single-port SPAs use only the port number 0. To configure or monitor SPA interfaces, you need to specify the physical location of the SIP, SPA, and interface in the CLI. The interface address format is slot / subslot / port, where:

• slot —Specifies the chassis slot number in the Cisco 7600 series router where the SIP is installed.
• subslot —Specifies the secondary slot of the SIP where the SPA is installed.
• port —Specifies the number of the individual interface port on a SPA.

The following example shows how to specify the first interface (0) on a SPA installed in the first subslot of a SIP (0) installed in chassis slot 3:

This command shows a serial SPA as a representative example, however the same slot / subslot / port format is similarly used for other SPAs (such as ATM and POS) and other non-channelized SPAs.

For the 8-Port Channelized T1/E1 SPA, the interface address format is slot/subslot/port : channel-group, where:

• channel-group—Specifies the logical channel group assigned to the timeslots within the T1 link.

For more information about identifying slots and subslots, see the “Identifying Slots and Subslots for SIPs, SSCs, and SPAs” section.

Optional Configurations

There are several standard, but optional, configurations that might be necessary to complete the configuration of your serial SPA.

• Configuring Framing
• Configuring Encapsulation
• Configuring the CRC Size for T1
• Configuring FDL
• Configuring Multilink Point-to-Point Protocol (Hardware-based)
• Configuring MLFR for T1/E1
• Invert Data on the T1/E1 Interface
• Changing a Channel Group Configuration
• Configuring Multipoint Bridging
• Configuring Bridging Control Protocol Support
• Configuring BCP on MLPPP
• LFI Guidelines
• HW MLPPP LFI Guidelines
• FRF.12 LFI Guidelines
• Configuring QoS Features on Serial SPAs

Configuring Framing

Framing is used to synchronize data transmission on the line. Framing allows the hardware to determine when each packet starts and ends. To configure framing, use the following commands.

Verifying Framing Configuration

Use the show controllers command to verify the framing configuration:

Configuring Encapsulation

When traffic crosses a WAN link, the connection needs a Layer 2 protocol to encapsulate traffic. To set the encapsulation method, use the following commands:

Verifying Encapsulation

Use the show interfaces serial command to verify encapsulation on the interface:

Configuring the CRC Size for T1

All 8-Port Channelized T1/E1 SPA interfaces use a 16-bit cyclic redundancy check (CRC) by default, but also support a 32-bit CRC. CRC is an error-checking technique that uses a calculated numeric value to detect errors in transmitted data. The designators 16 and 32 indicate the length (in bits) of the frame check sequence (FCS). A CRC of 32 bits provides more powerful error detection, but adds overhead. Both the sender and receiver must use the same setting.

CRC-16, the most widely used CRC throughout the United States and Europe, is used extensively with WANs. CRC-32 is specified by IEEE 802 and as an option by some point-to-point transmission standards. It is often used on Switched Multimegabit Data Service (SMDS) networks and LANs.

To set the length of the cyclic redundancy check (CRC) on a T1 interface, use these commands:

Verifying the CRC Size

Use the show interfaces serial command to verify the CRC size set on the interface:

Configuring FDL

Facility Data Link (FDL) is a 4-kbps channel provided by the Extended Super Frame (ESF) T1 framing format. The FDL performs outside the payload capacity and allows you to check error statistics on terminating equipment without intrusion.

Verifying FDL

Use the show controllers t1 command to verify the fdl setting:

Router# show controllers t1

Configuring Multilink Point-to-Point Protocol (Hardware-based)

Multilink Point to Point Protocol (MLPPP) allows you to combine T1 or E1 lines into a bundle that has the combined bandwidth of multiple T1/E1 lines. You choose the number of bundles and the number of T1 or E1 lines in each bundle.

MLPPP for T1/E1 Configuration Guidelines

The required conditions are:

• Only T1 or E1 links in a bundle
• All links on the same SPA
• Maximum of 12 links in a bundle.

Note Some notes about hardware-based MLPPP:

Only 3 fragmentation sizes are possible 128, 256 and 512 bytes

Fragmentation is enabled by default, default size is 512 bytes

Fragmentation size is configured using the ppp multilink fragment-delay command after using the interface multilink command. The least of the fragmentation sizes (among the 3 sizes possible) satisfying the delay criteria is configured. (For example, a 192 byte packet causes a delay of 1 millisecond on a T1 link, so the nearest fragmentation size is 128 bytes.)

The show ppp multilink command indicates the MLPPP type and the fragmentation size:

Router# show ppp multilink
Multilink1, bundle name is Patriot2
Bundle up for 00:00:13
Bundle is Distributed
0 lost fragments, 0 reordered, 0 unassigned
0 discarded, 0 lost received, 206/255 load
0x0 received sequence, 0x0 sent sequence
Member links: 2 active, 0 inactive (max not set, min not set)
Se4/2/0/1:0, since 00:00:13, no frags rcvd
Se4/2/0/2:0, since 00:00:10, no frags rcvd
Distributed fragmentation on. Fragment size 512. Multilink in Hardware.

Fragmentation is disabled explicitly by using the no ppp multilink fragmentation command after using the interface multilink command.

Create a Multilink Bundle

To create a multilink bundle, use the following commands:

Assign an interface to a Multilink Bundle

To assign an interface to a multilink bundle, use the following commands:

Configuring fragmentation size on an MLPPP Bundle (optional)

To configure the fragmentation size on a multilink PPP bundle, use the following commands:

Disabling the fragmentation on an MLPPP Bundle (optional)

To assign an interface to a multilink bundle, use the following commands:

Verifying Multilink PPP

Use the show ppp multilink command to verify the PPP multilinks:

Configuring MLFR for T1/E1

Multilink Frame Relay (MLFR) allows you to combine T1/E1 lines into a bundle that has the combined bandwidth of multiple T1/E1 lines. You choose the number of bundles and the number of T1/E1 lines in each bundle. This allows you to increase the bandwidth of your network links beyond that of a single T1/E1 line.

MLFR for T1/E1 Configuration Guidelines

MLFR will function in hardware if all of the following conditions are met:

• Only T1 or E1 member links
• All links are on the same SPA
• Maximum of 12 links in a bundle

Create a Multilink Bundle

To create a multilink bundle, use the following commands:

Note When you remove a linecard from a slot which has MFR or MLP configured, you should first remove the MFR or MLP configurations from the links before you add links from other slots. If you do not remove the configurations, then the links from other slots cannot be added to these bundles because it is already associated with another slot which is removed.

Assign an Interface to a Multilink Bundle

To assign an interface to a multilink bundle, use the following commands:

Verifying Multilink Frame Relay

Use the show frame-relay multilink detailed command to verify the Frame Relay multilinks:

Invert Data on the T1/E1 Interface

If the interface on the 8-Port Channelized T1/E1 SPA is used to drive a dedicated T1 line that does not have B8ZS encoding, you must invert the data stream on the connecting CSU/DSU or on the interface. Be careful not to invert data on both the CSU/DSU and the interface, as two data inversions will cancel each other out. To invert data on a T1/E1 interface, use the following commands:

Changing a Channel Group Configuration

To alter the configuration of an existing channel group, the channel group needs to be removed first. To remove an existing channel group, use the following commands:

Configuring Multipoint Bridging

Multipoint bridging (MPB) enables the connection of multiple ATM PVCs, Frame Relay PVCs, BCP ports, and WAN Gigabit Ethernet subinterfaces into a single broadcast domain (virtual LAN), together with the LAN ports on that VLAN. This enables service providers to add support for Ethernet-based Layer 2 services to the proven technology of their existing ATM and Frame Relay legacy networks. Customers can then use their current VLAN-based networks over the ATM or Frame Relay cloud. This also allows service providers to gradually update their core networks to the latest Gigabit Ethernet optical technologies, while still supporting their existing customer base.

For MPB configuration guidelines and restrictions and feature compatibility tables, see the “Configuring Multipoint Bridging” section.

Configuring Bridging Control Protocol Support

The Bridging Control Protocol (BCP) enables forwarding of Ethernet frames over SONET networks and provides a high-speed extension of enterprise LAN backbone traffic through a metropolitan area. The implementation of BCP on the SPAs includes support for IEEE 802.1D, IEEE 802.1Q Virtual LAN (VLAN), and high-speed switched LANs.

For BCP configuration guidelines and restrictions and feature compatibility tables, see the “BCP Feature Compatibility by SIP and SPA Combination”.

Configuring BCP on MLPPP

BCP on MLPPP Configuration Guidelines

• Only Distributed MLPPP is supported
• Only channelized interfaces allowed, and member links must be from the same controller card
• Only trunk port BCP is supported on MLPPP
• Bridging can be configured only on the bundle interface

Note BCP on MLPPP operates only in trunk mode. For more inforation on trunk mode, see the “Configuring BCP in Trunk Mode” section.

Note When you manually configure the MTU and MRRU values on the bundle interface with BCP on MLPPP, you should set the MRRU value to atleast 20 bytes more than the MTU value. This configuration ensures that the packets wth size up to the configured MTU value on the multilink interface are not dropped because of the MRRU restrictions.

Configuring BCP on MLPPP Trunk Mode

To configure BCP on MLPPP trunk mode, perform these steps:

Verifying BCP on MLPPP Trunk Mode

To display information about Multilink PPP, use the show ppp multilink command in EXEC mode.

The following shows an example of show ppp multilink :

FRF.12 Guidelines

FRF.12 functions in hardware. Note the following:

• Only 3 fragmentation sizes are available: 128 bytes, 256 bytes, and 512 bytes.
  The supported fragment sizes - 128, 256 and 512 - include the FRF and NLPID headers in addition to the payload.
• If you have a configuration where a C7600 router acts as a Provider Edge(PE) router between Customer Edge(CE) routers, you can configure C7600 in plain Frame Relay or Frame Relay Fragmentation mode. If you enable Frame Relay Fragmentation only at the CE routers and C7600 acts as a plain Frame Relay interface, the configuration works fine. In a configuration of C7600 with any of the three SPAs(8-Port Channelized T1/E1 SPA,1-Port Channelized OC-3/STM-1 SPA or 2 or 4-Port CT3 SPA), where Frame Relay is configured on the serial interface and Frame Relay Fragmentation is enabled in any of the sub interfaces, the fragmented packets may be dropped in the transparant DLCIs. If you want such a configuration to work, you should set the fragment size value on the main interface larger than any CE router fragmentation size using the command frame-relay fragment x end-to-end, where x is the fragmentation size on the main interface.

LFI Guidelines

LFI can function two ways—using FRF.12 or MLPPP. MLPPP LFI can be done in both hardware and software while FRF.12 LFI is done only in hardware.

HW MLPPP LFI Guidelines

LFI using MLPPP will function only in hardware if there is just one member link in the MLPPP bundle. The link can be a fractional T1 or full T1. Note the following:

• The ppp multilink interleave command needs to be configured to enable interleaving.
• Only three fragmentation sizes are supported: 128 bytes, 256 bytes, and 512 bytes.
• Fragmentation is enabled by default, the default size being 512 bytes.
• A policy-map having a priority class needs to applied to main interface.
• When hardware-based LFI is enabled, fragmentation counters are not displayed.

FRF.12 LFI Guidelines

LFI using FRF.12 is always done is hardware. Note the following:

• The fragmentation is configured at the main interface
• Only 3 fragmentation sizes are available: 128 bytes, 256 bytes, and 512 bytes.
• A policy-map having a priority class needs to applied to main interface.

Configuring QoS Features on Serial SPAs

The SIPs and SPAs support many QoS features using modular QoS CLI (MQC) configuration. For information about the QoS features supported by the serial SPAs, see the “Configuring QoS Features on a SIP” section.

Saving the Configuration

Caution When you swap a SPA-8XCHT1/E1-V2 (Pb-free) SPA with a SPA-8XCHT1/E1 (Pb) SPA or vice-versa, configuration is not retained.

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To save your running configuration to nonvolatile random-access memory (NVRAM), use the following command in privileged EXEC configuration mode:

For more information about managing configuration files, refer to the Cisco IOS Configuration Fundamentals Configuration Guide, Release 12.2 and Cisco IOS Configuration Fundamentals Command Reference, Release 12.2 publications.

Verifying Per-Port Interface Status

To find detailed interface information on a per-port basis for the 8-Port Channelized T1/E1 SPA, use the show interfaces serial command.

The following example provides sample output for interface port 0 on the SPA located in the first subslot of the SIP installed in slot 6 of a Cisco 7609 router:

Framing and Encapsulation Configuration Example

The following example sets the framing and encapsulation for the controller and interface:

CRC Configuration Example

The following example sets the CRC size for the interface:

Facility Data Link Configuration Example

The following example configures Facility Data Link:

MLPPP Configuration Example

The following example creates a PPP Multilink bundle:

MFR Configuration Example

The following example configures Multilink Frame Relay (MFR):

Invert Data on the T1/E1 Interface Example

The following example inverts the data on the serial interface: