Specifications

Table Of Contents

12 Release Notes for Cisco uBR904 Cable Access Router for Cisco IOS Release 12.0(7)T

Important Notes

Caution After you connect a laptop PC to the Cisco uBR904 cable access router console port and

save conﬁguration changes (provided your network supports remote conﬁguration) power cycle the

Cisco uBR904 cable access router if you’re not using the laptop at the subscriber site. This is

important when the Cisco uBR904 cable access router is conﬁgured to operate in a

DOCSIS-compliant bridging mode. Power cycling the Cisco uBR904 cable access router ensures the

laptop PC does not remain in the list of CPE devices at the subscriber site for the Cisco uBR904

cable access router to support. Only reinitialization of the cable interface clears out the bridge table

and resets the counter that speciﬁes the number of CPE devices being bridged.

Note This behavior is in accordance with DOCSIS. For conﬁgurations including Cisco 7200 series

CMTS equipment, enter the clear cable modem host mac address command to clear the laptop PC

from the headend security access control tables.

Layer 2 Tunneling Protocol

Implementation of L2TP in Cisco IOS Release 12.0(5)T is dependent on a PPP connection

supported on one of the directly attached interfaces. A dial-up PPP connection is required in order

to initiate an L2TP Tunnel connection. This is a requirement of the L2TP Access Concentrator

(LAC). In Cisco IOS Release 12.0(5)T, the Cisco uBR904 cable access router cannot function as the

LAC; it can only function as the L2TP Network Server (LNS), which terminates a tunnel created

elsewhere in the network.

Note The L2TP feature is removed in Cisco IOS Release 12.0(7)T.

Important Notes

This section contains important information about using your Cisco IOS Release 12.0 T software.

Last Maintenance Release of Cisco IOS Release 12.0 T

Cisco IOS Release 12.0(6)T has been renamed 12.0(7)T to align this release with the 12.0(7)

mainline release. The closed caveats for Release 12.0(7)T are identical to the caveats closed in the

12.0(7) mainline release. There was no change in the feature content of the renamed release—the

features in 12.0(6)T are the same as 12.0(7)T. Release 12.0(7)T is the last maintenance release of the

12.0 T release train.

Customers needing closure of caveats for the 12.0 T features should migrate to the 12.1 mainline

release, which has the complete feature content of Release 12.0 T and will eventually reach General

Deployment (GD). Release 12.0 T is a superset of the 12.0 mainline release, so all caveats closed in

the 12.0 mainline are also closed in 12.0 T.

Supplemental and Corrected Text for the Online Feature Module

Troubleshooting Tips for the Cisco uBR904 Cable Modem, page 11, indicates: “Some CATV

systems use alternative frequency plans such as the IRC (Incrementally Related Carrier) and HRC

(Harmonically Related Carrier) plans. Most of the IRC channel slots overlap the EIA plan. The HRC

plan is not supported by Cisco’s cable modems since so few cable plants are using this plan.”