Specifications

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Release Notes for Cisco 7000 Family for Cisco IOS Release 12.1 T
78-10811-05
New and Changed Information
New Software Features in Release 12.1(3)T
The following new software features are supported by the Cisco 7000 family for Cisco IOS
Release 12.1(3)T:
Bridging Between IEEE 802.1Q vLANs
Platforms: Cisco 7100 series, Cisco 7200 series, and Cisco 7500 series routers
The Bridging Between IEEE 802.1Q vLANs feature provides the ability to connect a network of hosts
over a simple bridging-access device to a remote access concentrator. This feature supports the
following IEEE 802.1Q (dot1q) functionality:
Integrated routing and bridging (IRB) supports connectivity for multiple VLANs using a Bridge
Group Virtual Interface (BVI) to associate a bridge group.
Transparent bridging (TB) supports connectivity for multiple VLANs bridged between dot1q
interfaces and other interface encapsulations or other types of interface media.
Per-VLAN Spanning Tree (PVST+) for IEEE 802.1Q trunks supports dot1q trunks to map multiple
spanning trees to a single spanning tree.
This feature enables interoperability and compatibility between dot1q encapsulated interfaces and all
supported interface medias, such as Inter-Switch Link (ISL) encapsulated interfaces. The packets on the
dot1q link contain a standard Ethernet or Fast Ethernet frame and the VLAN information associated
with that frame. To interoperate with existing Cisco routers, run spanning tree per-VLAN over ISL or
PVST, where a single spanning tree caters to every VLAN in the domain, PVST+ runs spanning tree on
a per VLAN basis, and a default VLAN 1 spanning tree (also called Common Spanning Tree) tunnels
to the IEEE 802.1Q specific VLAN.
CEF Support for IP Routing Between IEEE 802.1Q vLANs
Platforms: Cisco 7200 series and Cisco 7500 series routers
Beginning with this release, Cisco Express Forwarding (CEF) is supported on interfaces on which IEEE
802.1Q encapsulation has been enabled at the subinterface level. You no longer have to disable CEF
operation on interfaces that are using IEEE 802.1Q encapsulation on VLAN subinterfaces.
Circuit Interface Identification MIB
Platforms: Cisco 7500 series routers
The Circuit Interface Identification MIB feature adds support for a new Cisco enterprise MIB, used to
assist in SNMP monitoring of circuit-based interfaces. The Circuit Interface MIB
(CISCO-CIRCUIT-INTERFACE-MIB) provides a MIB object, which can be used to identify individual
circuit-based interfaces (for example, interfaces using ATM or Frame-Relay). This user-specified
identification is then returned when linkup and linkdown SNMP traps are generated for the interface.
The Circuit Interface MIB consists of a single table, with each row comprising a sequence of two
objects: circuit interface description (cciDescr) and circuit interface status (cciStatus). The cciDescr
object is used to identify circuits using a textual description of up to 255 characters specified by the user
(note that MIB objects are modified using network management system applications, and cannot be
configured using the Cisco IOS command-line interface). When the row is created by a user, a value is
set for the cciDescr object. The table is indexed by ifIndex from the IF-MIB. The cciStatus is the
RowStatus object for the rows in the table. The cciStatus object can be set to only two values by the
user: createAndGo(4), which creates a new row, and destroy(6), which removes an existing row. If the