Installation guide

Release Notes for Cisco uBR7200 Series for Cisco IOS Release 12.1 T

78-10643-04 Rev. B0

New and Changed Information

AutoInstall Using DHCP for LAN Interfaces feature also allows the routing device to recognize IP

address allocation messages coming from regular BOOTP servers, providing a seamless transition for

those devices already using BOOTP servers for AutoInstall. Additionally, this feature allows for the

uploading of configuration files using unicast Trivial File Transfer Protocol (TFTP).

For further details, see the following document on CCO:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121newft/121t/121t5/dt_dhcpa.htm

Cable Downstream Frequency Override CLI

The following new CLI command turns off the cable downstream frequency override on a per-interface

basis:

[no] cable downstream override

The default configuration enables the cable downstream frequency override. Only the [no] cable

downstream override command is displayed and allows the cable downstream frequency override to

be turned off.

Closed User Group Selection Facility Suppress Option

A closed user group (CUG) selection facility is a specific encoding element that allows a destination

data terminal equipment (DTE) to identify the CUG to which the source and destination DTEs belong.

The Closed User Group Selection Facility Suppress Option feature enables a user to configure an X.25

data communications equipment (DCE) interface or X.25 profile with a DCE station type to remove the

CUG selection facility from incoming call packets destined for the preferential CUG only or for all

CUGs. You can also remove the selection facility from a CUG with outgoing access (CUG/OA).

IGMP Version 3

Internet Group Management Protocol (IGMP) is a protocol used by IPv4 systems to report IP multicast

group memberships to neighboring multicast routers. On networks with hosts directly attached, IGMP

Version 3 (IGMPv3) adds support for “source filtering”, which enables a multicast receiver to signal to

a router which groups it wants to receive multicast traffic from, and from which source(s) this traffic is

expected. Based on this membership information, Cisco IOS software only forwards traffic that is

requested by the host or by other routers via Protocol Independent Multicast [PIM]) to that network. In

addition to restricting traffic on the network of the receiver host, IGMPv3 membership information can

also be propagated to multicast routing protocols to enable the forwarding of traffic from permitted

sources or to restrict traffic from denied sources along the entire multicast data delivery path.

In the Source Specific Multicast (SSM) feature, introduced in Cisco IOS Release 12.1(3)T, hosts must

explicitly include sources when joining a multicast group (this is known as “channel subscription”).

IGMPv3 is the industry-designated standard protocol for hosts to signal channel subscriptions in SSM.

In deployment cases where IGMPv3 cannot be used (for example, if it is not supported by the receiver

host or its applications), there are two other mechanisms to enable SSM: URL Rendezvous Directory

(URD) and IGMP Version 3 lite (IGMP v3lite). Both of these features were introduced with SSM in

Cisco IOS Release 12.1(3)T.

Interface Index Persistence

One of the most commonly used identifiers used in SNMP-based network management applications is

the Interface Index (ifIndex) value. IfIndex is a unique identifying number associated with a physical

or logical interface; as far as most software is concerned, the ifIndex is the "name" of the interface.