Cisco 2600 Series - Cisco IOS Release 12.2(8)YN
Available Languages
Table Of Contents
Release Notes for Cisco 2600 Series Routers for Cisco IOS Release 12.2(8) YN1
New Hardware and Software Features in Cisco IOS Release 12.2(8)YN1
New Hardware Features in Cisco IOS Release 12.2(8)YN
New Software Features in Cisco IOS Release 12.2(8)YN
ATM Cell Loss Priority (CLP) Bit Marking
Bundling of ATM Interfaces Using MLPPP
Compressed Real-Time Transport Protocol
Caveats for Cisco IOS Release 12.2(8) YN
Open Caveats—Cisco IOS Release 12.2(8) YN1
Resolved Caveats—Cisco IOS Release 12.2(8) YN1
Open Caveats—Cisco IOS Release 12.2(8) YN
Resolved Caveats—Cisco IOS Release 12.2(8) YN
Release Notes for Cisco 2600 Series Routers for Cisco IOS Release 12.2(8) YN1
January 27, 2003
Cisco IOS Release 12.2(8) YN1
OL-3463-01-A0
These release notes for the Cisco 2600 series routers describe the enhancements provided in Cisco IOS Release 12.2(8) YN1. These release notes are updated as needed.
For a list of the software caveats that apply to Cisco IOS Release 12.2(8) YN, see the "Caveats for Cisco IOS Release 12.2(8) YN" section and Caveats for Cisco IOS Release 12.2 T. The caveats document is updated for every maintenance release and is located on Cisco.com and the Documentation CD-ROM.
Use these release notes with Cross-Platform Release Notes for Cisco IOS Release 12.2 T located on Cisco.com and the Documentation CD-ROM.
Cisco recommends that you view the field notices for this release to see if your software or hardware platforms are affected. If you have an account on Cisco.com, you can find field notices at http://www.cisco.com/kobayashi/support/tac/fn_index.html. If you do not have a Cisco.com login account, you can find field notices at http://www.cisco.com/kobayashi/support/tac/fn_index.html
Contents
These release notes describe the following topics:
•
Caveats for Cisco IOS Release 12.2(8) YN
Inheritance Information
Cisco IOS Release 12.2(8) YN is based on Cisco IOS Release 12.2(8)T. All features in Cisco IOS Release 12.2(8)T are in Cisco IOS Release 12.2(8) YN.
Table 1 lists sections of the Cross-Platform Release Notes for Cisco IOS Release 12.2 T that apply to Cisco IOS Release 12.2(8) YN.
Table 1 References for the Cross-Platform Release Notes for Cisco IOS Release 12.2 T
•
•
•
•
•
Click Platform-Specific Information and Cisco 2600 Series Routers at
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/ 122relnt/xprn122t/122tfeat.htm.•
•
Click Cross-Platform System Requirements at http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/ 122relnt/xprn122t/122treqs.htm.
•
•
•
Go to
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/ 122relnt/xprn122t/122tnewf.htm.
•
•
•
Go to http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/ 122relnt/xprn122t/122tdocs.htm.
System Requirements
This section describes the system requirements for Cisco IOS Release 12.2(8)YN and includes the following sections:
Memory Recommendations
Feature Set Tables
The Cisco IOS software is packaged in feature sets consisting of software images—depending on the platform. Each feature set contains a specific set of Cisco IOS features.
Cisco IOS Release 12.2(8) YN1 supports the same feature sets as Cisco IOS Release 12.2(8) T, but Cisco IOS Release 12.2(8) YN1 can include new features supported by the Cisco 2600 series routers.
Caution
Table 3 lists the features and feature sets supported by the Cisco 2600 series routers in Cisco IOS Release 12.2(8)YN1 and uses the following conventions:
•
•
•
Note
New and Changed Information
The following sections list the new hardware and software features supported by the Cisco 2600 series routers for Cisco IOS Release 12.2(8) YN1.
New Hardware and Software Features in Cisco IOS Release 12.2(8)YN1
There are no new hardware or software features supported by the Cisco 2600 series routers for Cisco IOS Release 12.2(8)YN1.
New Hardware Features in Cisco IOS Release 12.2(8)YN
There are no new hardware features supported by the Cisco 2600 series routers for Cisco IOS Release 12.2(8)YN.
New Software Features in Cisco IOS Release 12.2(8)YN
The following new software features are supported by the Cisco 2600 series routers for Cisco IOS Release 12.2(8)YN.
ATM Cell Loss Priority (CLP) Bit Marking
When congestion occurs in an ATM network, ATM cells are discarded. One way to control which cells are discarded is to use cell loss priority (CLP) bit marking in the header of each cell. You can set the CLP bit to either 1 or 0. Those cells that have the CLP bit set to 1 are always discarded before any cells that have the CLP bit set to 0.The ATM CLP Bit Marking feature allows you to control the CLP setting on the Cisco routers. The marking of the CLP bit is implemented on a per-packet basis so that the CLP bit of every ATM cell that belongs to a particular packet is set to either 0 or 1.
Bundling of ATM Interfaces Using MLPPP
The Bundling of ATM Interfaces Using Multilink PPP (MLP) feature supports other quality of service (QoS) features, such as LLQ and CBWFQ and link fragmentation and interleaving (LFI). The bundling feature supports the other QoS features over a multilink MLP bundle for which members of the bundle are defined across physically different DSL interfaces. The bundling occurs at the ATM layer through ATM permanent virtual circuits (PVCs).
Compressed Real-Time Transport Protocol
The Real-Time Transport Protocol (RTP) feature, as described in RFC 1889, is used to carry real-time data for voice and video applications. For a typical Voice over IP (VoIP) application, the payload portion of the packet can be smaller than the header. For instance, using the G.729 codec, the payload is 20 bytes, but the IP, User Data Protocol (UDP), and RTP header is 40 bytes. Sending the IP, UDP, and RTP header across a slow link without compressing it is inefficient. The Compressed Real-Time Transport Protocol (cRTP) feature, as defined in RFC 2508, addresses this inefficiency by making smaller VoIP packet headers. The basic idea behind cRTP is that although several fields in the IP, UDP, and RTP header change from packet to packet, the difference in these fields from packet to packet is constant. The compression scheme in cRTP is to encode the header to reduce the size of information to be transmitted. With cRTP, a 40-byte IP, UDP, and RTP header of a VoIP packet can be compressed to 2 to 4 bytes per packet, yielding approximately 11.2 kbps of bandwidth for a G.729 codec call that uses RTP.
Tunable Tx-Ring Buffer
The transmission (tx) ring is the first-in, first-out (FIFO) buffer used to hold frames before transmission at the DSL driver level. The tx ring defines the maximum number of packets that can wait for transmission at Layer 2. The tx ring complements the ability of LLQ to minimize jitter and latency of voice packets. For maximum voice quality, use a low tx ring setting. For maximum data throughput, use a high tx ring setting. You can configure the size of the tx ring for each permanent virtual circuit (PVC). The default value is 60. However, the value of the setting can be 2 through 60 on Cisco 1700, Cisco 2600, and Cisco 3600 series routers. A low tx ring setting, such as 2 or 3, is required for latency-critical traffic. For example, when the tx ring limit is configured as 3 and LLQ is configured on the PVC, the worst case delay for a voice packet is the time required to transmit three data packets. When the buffering is reduced by configuring the tx ring limit, the delay for voice packets is reduced by a combination of the tx ring and LLQ mechanism.
Frame Relay - FRF.5 and FRF.8
To communicate over WANs, end-user stations and the network cloud typically must use the same type of transmission protocol. This limitation has prevented differing networks such as Frame Relay and ATM from being linked. The Frame Relay-to-ATM service interworking feature allows Frame Relay and ATM networks to exchange data despite differing network protocols. The functional requirements for linking Frame Relay and ATM networks are provided by the Frame Relay/ATM PVC Service Interworking Implementation Agreement specified in Frame Relay Forum (FRF) documents FRF.5 and FRF.8. The FRF.5 and FRF.8 interworking functions involve multiplexing PVCs between Frame Relay and ATM networks and mapping the control bits between Frame Relay frame headers and ATM cell headers. FRF.5 and FRF.8 are necessary for ATM-based features to interwork with Frame-Relay-based IP class of service features.
Caveats for Cisco IOS Release 12.2(8) YN
Caveats describe unexpected behavior in Cisco IOS software releases. Severity 1 caveats are the most serious caveats; severity 2 caveats are less serious. Severity 3 caveats are moderate caveats, and only select severity 3 caveats are included in the caveats document.
This section contains open and resolved caveats for the current Cisco IOS maintenance release.
All caveats in Cisco IOS Release 12.2 and Cisco IOS Release 12.2 T that apply to the Cisco 2600 series routers are also in Cisco IOS Release 12.2(8) YN1.
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, which lists severity 1 and 2 caveats and select severity 3 caveats and is located on Cisco.com and the Documentation CD-ROM.
Note
Open Caveats—Cisco IOS Release 12.2(8) YN1
This section documents possible unexpected behavior by Cisco IOS Release 12.2(8) YN 1and describes only severity 1 and 2 caveats and select severity 3 caveats.
•
Symptom: A Cisco Router that has run out of processor memory may unexpectedly reload due to a bus error at an invalid address if there is an attempt to secure shell (SSH) into a vty port, which fails due to a process creation failure. A SYS-2-CFORKMEM error message will appear right before the restart.
Workaround: Disable SSH access to your router.
Resolved Caveats—Cisco IOS Release 12.2(8) YN1
All the caveats listed in this section are resolved in Cisco IOS Release 12.2(8) YN1 and describes only severity 1 and 2 caveats and select severity 3 caveats.
•
Symptom: For newly installed WIC-1SHDSL-FDG followed by a soft reload, ping may fail for this SHDSL ATM interface. This happens very rarely and can be solved by issuing a shutdown or no shutdown command on the interface. The cause for this is known now and a fix is to be implemented soon.
Workaround: Issue a shutdown or no shutdown command on the interface.
•
Symptom: The minimum value of the TX ring that can be configured on a private virtual circuit (PVC) over a ADSL/G.SHDSL interface is changed to 2 on Cisco 2600, Cisco 3600, and Cisco 3700 platforms.
Workaround: There is no workaround.
•
The format of the MAC address of the wireless client in the calling-station-id field of the Accounting Start does not match the format of the MAC address in the calling-station-id field of the Access Requests. SSG is unable to correlate and create a host object. The host object is necessary for the solution to work. The same problem exists with the Accounting Stop.
•
Certain Cisco products containing support for the Secure Shell (SSH) server are vulnerable to a Denial of Service (DoS) if the SSH server is enabled on the device. A malformed SSH packet directed at the affected device can cause a reload of the device. No authentication is necessary for the packet to be received by the affected device. The SSH server in Cisco IOS is disabled by default.
Cisco will be making free software available to correct the problem as soon as possible.
The malformed packets can be generated using the SSHredder test suite from Rapid7, Inc. Workarounds are available. The Cisco PSIRT is not aware of any malicious exploitation of this vulnerability.
This advisory is available at the following URL:
http://www.cisco.com/warp/public/707/ssh-packet-suite-vuln.shtml
•
Certain Cisco products containing support for the Secure Shell (SSH) server are vulnerable to a Denial of Service (DoS) if the SSH server is enabled on the device. A malformed SSH packet directed at the affected device can cause a reload of the device. No authentication is necessary for the packet to be received by the affected device. The SSH server in Cisco IOS is disabled by default.
Cisco will be making free software available to correct the problem as soon as possible.
The malformed packets can be generated using the SSHredder test suite from Rapid7, Inc. Workarounds are available. The Cisco PSIRT is not aware of any malicious exploitation of this vulnerability.
This advisory is available at the following URL:
http://www.cisco.com/warp/public/707/ssh-packet-suite-vuln.shtml
Open Caveats—Cisco IOS Release 12.2(8) YN
This section documents possible unexpected behavior by Cisco IOS Release 12.2(8) YN and describes only severity 1 and 2 caveats and select severity 3 caveats.
•
Symptom: When using T1/E1 WICs, the serial interface created by configuring channel-group with T1/E1 is not reflected in the clock rate values when issuing show controller atm.
Workaround: There is no workaround.
•
Symptom: G.SHDSL remains trained with previous operating mode after new mode is configured on the interface.
Workaround: Shut/no shut on the interface has to be issued to retrain.
•
Symptom: Configuring tx-ring-limit as 3 may degrade output.
Workaround: Configure 4 and onwards until 60 for the tx-ring-limit. For lower latency, 4 is the preferred value until this DDTS is resolved.
Resolved Caveats—Cisco IOS Release 12.2(8) YN
Because Cisco IOS Release 12.2(8) YN1 is the initial base release, there are no resolved caveats. For a list of the resolved caveats, refer to the next set of release notes for this release version.
Feedback