User guide

New and Changed Information
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Release Notes for Cisco 2500 Series for Cisco IOS Release 12.0 T
78-5563-07 Rev.H0
WCCPv2 provides enhancements to WCCPv1, including:
• Multihome router support enables multiple co-located, WCCP-enabled routers to share a cache
cluster.
• Improved security enables MD5 digital signature authentication (RFC 1321) to be used in Cache
Engine/WCCP router communications.
• Redirection of non-port 80 traffic enables WCCP-enabled routers to transparently redirect traffic
based on any TCP port (for example, FTP and NNTP traffic), in addition to HTTP traffic. Cache
Engine-side support for non-port 80 traffic will be provided in the future.
• Content bypass support—When a Cache Engine rejects a request and sends it back to the
WCCP-enabled router, the router knows not to redirect the request to the Cache Engine again.
• Flexible content distribution within a cache cluster—Various hashing parameters can be used to
determine content distribution within a cache cluster.
X.25 Load Balancing
As the number of users accessing the same host has grown, competition for these application resources
has become a problem. Internet service providers (ISPs) have had to increase the number of users they
could support by increasing the number of X.25 lines to the host.
In order to support a large number of virtual circuits (VCs) to a particular destination, configuration of
more than one serial interface to that destination was needed. When a serial interface is configured to
support X.25, there is a fixed number of VCs available for use.
Using a facility called “hunt-group” (the method for X.25 load balancing), a switch is able to view a
pool of X.25 lines going to the same host as one address and assign VCs on an “idle logical channel”
basis. With this feature, X.25 calls can be load-balanced among all configured outgoing interfaces to
fully use and balance all managed lines. The benefits include, the choice of two load-balancing
distribution methods (rotary or vc-count) and improved performance of serial lines.
New Software Features in Release 12.0(2)T
There are no new features supported by the Cisco 2500 series in Cisco IOS Release 12.0(2)T.
New Software Features in Release 12.0(1)T
The following new software enhancements are supported by the Cisco 2500 series in Release 12.0(1)T
and later releases.
RSM/TR-VLAN
The Token Ring VLAN support on the Route Switch Module (RSM) enables a Catalyst 5000 switch to
provide the functionality of bridging and multi-protocol routing for Token Ring VLANs. The
installation of an RSM in a Catalyst 5000 supplements the existing switching capabilities with the
functionality of a standalone router that performs inter-VLAN routing and bridging. If the Token Ring
RSM is associated with a VIP2 board, it provides direct external network connections through a variety
of media using the standard port adapters on the VIP2 and offers functionality similar to a Cisco 7500
series router.