Table Of Contents
Release Notes for Cisco MGX-RPM-1FE-CP Back Card for Cisco IOS Release 12.2(8)MC2
July 29, 2002
Cisco IOS Release 12.2(8)MC2
These release notes are for the Cisco MGX-RPM-1FE-CP for Cisco IOS Release 12.2(8)MC2.These release notes are updated as needed to describe new features, memory requirements, hardware support, software platform deferrals, and changes to the microcode and related documents.
For a list of the software caveats that apply to Cisco IOS Release 12.2(8)MC2, see the "Caveats in Cisco IOS Release 12.2(8)MC2" section.
To review the release notes for Cisco IOS Release 12.2, go to www.cisco.com and click Technical Documents. Select Release 12.2 from the Cisco IOS Software drop-down menu. Then click Cisco IOS Release Notes > Cisco IOS Release 12.2.
This document contains the following sections:
The MGX-RPM-1FE-CP (one-port, Fast Ethernet-Co-processor) back card is a Cisco MGX 8850 RPM-PR back card that off-loads the following processes from the Route Processor Module (RPM-PR):
•Compression/decompression of Real-time Transport Protocol (RTP)/User Datagram Protocol (UDP) headers (cRTP/cUDP)
•Multiplexing/demultiplexing of Point-to-Point Protocol (PPP) frames
The MGX-RPM-1FE-CP back card is designed to be used with an MGX 8850 that is equipped with one or more RPM-PRs and that terminates some number of T1 lines. Each MGX-RPM-1FE-CP back card has a termination capacity of up to eight T1s (four per MLP bundle). The MGX-RPM-1FE-CP is only supported with the MLP encapsulation.
The MGX-RPM-1FE-CP back card contains one Fast Ethernet (100Base-Tx) interface. The interface has an RJ45 connector that is used to connect the card to a Category 5 un-shielded twisted pair (UTP) cable. Both half- and full-duplex operation are supported.
MGX-RPM-1FE-CP Back Card in an IP-RAN of a Mobile Wireless Network
The MGX-RPM-1FE-CP back card off loads the compression/decompression of RTP/UDP headers and the multiplexing/demultiplexing of PPP frames.
The supported use of the MGX-RPM-1FE-CP back card is within an IP-RAN of a mobile wireless network. In mobile wireless networks, radio coverage over a geographical space is provided by a network of radios and supporting electronics (Base Transceiver Station or BTS) distributed over a wide area. Each radio and supporting electronics represents a "cell." In traditional networks, the radio signals or radio data frames collected in each cell are forwarded over a T1 (or similar low-speed, leased) line to a centralized Base Station Controller (BSC) where they are processed.
The implementation of the MGX-RPM-1FE-CP backcard in the IP-RAN solution requires the following components:
•Cisco MGX 8850
•MGX-RPM-1FE-CP back card
•BTS router (Cisco MWR 1900 Mobile Wireless Edge Router)
The solution uses OSPF as the routing protocol and requires MLP for transmission of the packets between the aggregation node (MGX8850) and the BTS. It requires you to configure the following:
•The Fast Ethernet (FE) interface to support OSPF. Enable multicast routing and indicate a Protocol Independent Multicast (PIM) mode.
•One or more PPP multilink interfaces with PPP mux and RTP header compression attributes.
•A virtual template for each of the multilink groups.
•A PVC under the switch subinterface that references the virtual template.
In addition, you must configure a connection between the PVC and the FRSM as well as a connection between the FRSM and the PVC.
For detailed information about the MGX-RPM-1FE-CP back card and its implementation in the IP-RAN solution, see the MGX-RPM-1FE-CP Back Card Installation and Configuration Note.
System Configuration Requirements
The MGX-RPM-1FE-CP requires the following system configuration:
•Cisco IOS 12.2(8) MC1 or a later Cisco IOS Release 12.2 MC image be installed on the corresponding Cisco MGX 8850 RPM-PR.
•The FE interface be configured via the Cisco IOS software command line interface.
Table 1 Memory Recommendations for the Cisco MGX 8850 RPM-PR
Platform Software Image Flash
32 MB Flash
256 MB DRAM
Determining the Software Version
To determine the version of Cisco IOS software copied on the RPM-PR, access the CLI of the RPM-PR and enter the show version command:rpm> show versionCisco Internetwork Operating System SoftwareIOS (tm) RPM Software (RPM-JS-M), Version 12.2(8)MC2, EARLY DEPLOYMENT RELEASESOFTWARE (fc1)
Upgrading to a New Software Release
For information about copying Cisco IOS images to RPM-PR Flash memory, see the RPM-PR Installation and Configuration document.
For general information about upgrading to a new Cisco IOS software release, refer to Software Installation and Upgrade Procedures located at the following URL:
New Features in the MGX-RPM-1FE-CP with Cisco IOS Release 12.2 MC Software
For detailed descriptions of each of these features, see the MGX-RPM-1FE-CP Back Card Installation and Configuration Note.
•Fast Ethernet—Single 10/100 FE port that can be used with or without cRTP/cUDP or PPP Multiplexing configured.
•cUDP/cRTP—Header compression that compresses UDP/RTP headers to 2 to 4 bytes.
•PPP Multiplexing—Method, as defined in RFC 3153, of sending multiple PPP encapsulated packets in a single PPP frame.
Limitations, Restrictions, and Important Notes
When working with a MGX-RPM-1FE-CP back card, please take note of the following limitations, restrictions, and important notes:
•Only one MGX-RPM-1FE-CP back card is supported per Cisco MGX 8850 RPM-PR.
•FE and multilink interfaces should be shut down before online insertion and removal (OIR) of the MGX-RPM-1FE-CP.
•The MGX-RPM-1FE-CP is only supported on the Cisco MGX 8850 RPM-PR.
•For PPP Multiplexing, MLP must be configured on the MGX-RPM-1FE-CP back card.
•For error messages to be stored, console logging must be configured.
•The IP MTU should be set to 512 bytes or less on multilink interfaces.
•The MGX-RPM-1FE-CP back card supports up to 8 multilink interfaces.
•MLP with LFI is not supported by the Cisco MWR 1900 router. Therefore, MLP with LFI must be disabled on peer devices connecting to the Cisco MWR 1900 router T1 MLP connections.
•To fully disable PPP Multiplexing, issue the no ppp mux command on the T1 interfaces of the routers at both ends of the T1 link. If PPP Multiplexing remains configured on one side of the link, that side will offer to receive PPP multiplexed packets.
Caveats in Cisco IOS Release 12.2(8)MC2
The following sections list and describe the open and closed caveats for the Cisco MGX-RPM-1FE-CP with Cisco IOS Release 12.2(8)MC2. Only severity 1 through 3 caveats are included.
Caveats describe unexpected behavior in Cisco IOS software releases. Severity 1 caveats are the most serious caveats, severity 2 caveats are less serious, and severity 3 caveats are the least serious of these three severity levels.
Caveats in Cisco IOS Releases 12.2 and 12.2 T are also in Cisco IOS Release 12.2(8)MC2. For information on caveats in Cisco IOS Release 12.2, see Caveats for Cisco IOS Release 12.2. For information on caveats in Cisco IOS Release 12.2 T, see Caveats for Cisco IOS Release 12.2 T. These two documents list severity 1 and 2 caveats and are located on CCO and the Documentation CD-ROM.
Note If you have an account with Cisco.com, you can use Bug Navigator II to find caveats of any severity for any release. To reach Bug Navigator II, Login to Cisco.com and click Software Center: Cisco IOS Software: Cisco Bugtool Navigator II. Another option is to go directly to http://www.cisco.com/support/bugtools.
The following caveat is open in Release 12.2(8)MC2.
If two MGX-RPM-1FE-CP back cards are installed at boot up or a second MGX-RPM-1FE-CP back card is installed in a running system, cryptic error messages might display and the system might become unstable. If the system be comes unstable, the instability could lead to a system crash.
Workaround: Only one MGX-RPM-1FE-CP back card is supported per RPM-PR. Do not install a second MGX-RPM-1FE-CP back card before removing the first back card. If two back cards are installed at any one time, we recommend that you reload the RPM-PR with only one MGX-RPM-1FE-CP back card installed.
The following caveat is resolved in Release 12.2(8)MC2.
Packet loss from the MGX 8850 RPM-PR to the Cisco MWR 1900 router increases at the Cisco MWR 1900 (as displayed using the show ip rtp header-compression command) when the MWR 1900 is reloaded and the MGX-RPM-PR switches are not.
To collect data for reporting back card and router issues, issue the following command:
•show tech-support—Displays general information about the router when it reports a problem.
•show logging—Displays information in the syslog history table.
This section contains information that was not included or was documented incorrectly in the MGX-RPM-1FE-CP Back Card Installation and Configuration Note. The heading in this section corresponds with the applicable section title in the documentation.
show ppp mux
The efficiency improvement factor calculation documented in the show ppp mux command section is incorrect. The correct improvement factor calculation uses bytes, not packets, and is as follows:
Multiplex efficiency improvement factor = 100 * (Total bytes saved) / (Total bytes received)
Where total bytes saved = bytes_received_at_muxer - bytes_sent_at_muxer.
Demultiplex efficiency improvement factor = 100 * (Total bytes saved) / (Total bytes sent)
Where total bytes saved = bytes_sent_at_demuxer - bytes_received_at_demuxer.
The following sections describe the documentation available related to the Cisco MGX-RPM-1FE-CP back card.These documents consist of hardware and software installation guides, Cisco IOS configuration guides and command references, system error messages, and other documents.
Documentation is available as printed manuals or electronic documents.
These documents are available for the Cisco MWR 1900 Mobile Wireless Edge Router on Cisco.com and the Documentation CD-ROM:
•MGX-RPM-1FE-CP Back Card Installation and Configuration Note
•RPM-PR Installation and Configuration
•Cisco MWR 1900 Mobile Wireless Edge Router
–Cisco MWR 1900 Hardware Installation Guide
–Cisco MWR 1900 Software Configuration Guide
–Cisco MWR 1900 Rack Mounting Instructions
–Cisco MWR 1900 Regulatory Compliance and Safety Information
•VWIC-2MFT-T1-DIR, VWIC-2MFT-E1-DIR Installation Instructions
Feature modules describe new features supported by Cisco IOS Release 12.2 MC and are updates to the Cisco IOS documentation set. A feature module consists of an overview of the feature, configuration tasks, and a command reference.
On Cisco.com at:
Technical Documents: Cisco IOS Software: Cisco IOS Release 12.2: New Feature Documentation: New Features in 12.2-Based Limited Lifetime Releases: New Features in Release 12.2 MC: New Features in Release 12.2 MC2
On the Documentation CD-ROM at:
Cisco Product Documentation: Cisco IOS Software Configuration: Cisco IOS Release 12.2: New Feature Documentation: New Features in 12.2-Based Limited Lifetime Releases: New Features in Release 12.2 MC: New Features in Release 12.2 MC2
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Obtaining Technical Assistance
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Cisco TAC Escalation Center
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This document is to be used in conjunction with the documents listed in the "Related Documentation" section.
Copyright © 2002, Cisco Systems, Inc.
All rights reserved.