User guide

27
Release Notes for Cisco 2500 Series for Cisco IOS Release 12.0 T
78-5563-07 Rev.H0
New and Changed Information
Using routing table intelligence in the network infrastructure, DistributedDirector transparently
redirects end user service requests to the closest responsive server, as determined by client-to-server
topological proximity and/or client-to-server response times, resulting in increased access performance
seen by the end user and reduced transmission costs.
For Cisco IOS Release 12.0(3)T, the functionality of DistributedDirector from 11.1 IA is migrated to
12.0 T. Cisco DistributedDirector is only available as a special hardware/software bundle on the Cisco
2501, 2502, and the 4700-M platforms.
DLSw+ Enhanced Load Balancing
In a network with multiple capable paths, the DLSw+ Load Balancing Enhancements feature improves
traffic load balancing between peers by distributing new circuits based on existing loads and the desired
ratio.
For each capable peer (peers that have the lowest or equal cost specified), the DLSw+ Load Balancing
feature calculates the difference between the desired and the actual ratio of circuits being used on a peer.
It detects the path that is underloaded in comparison to the other capable peers and assigns new circuits
to that path until the desired ratio is achieved.
DLSw+ Peer Clusters
The DLSw+ Peer Clusters feature reduces the explorer packet replication that typically occurs in a large
DLSw+ Peer Group design, where there are multiple routers connected to the same LAN.
The DLSw+ Peer Clusters feature associates DLSw+ peers (that are connected to the same LAN) into
logical groups. Once the multiple peers are defined in the same peer group cluster, the DLSw+ Border
Peer recognizes that it does not have to forward explorers to more than one member within the same
peer group cluster.
DLSw+ RSVP Bandwidth Reservation
The DLSw+ RSVP Bandwidth Reservation feature allows DLSw+ to reserve network bandwidth for the
DLSw+ TCP connection between DLSw+ peers.
Although it has been possible in the past to reserve bandwidth for a particular existing DLSw+ peer
connection through the RSVP CLI support in Cisco IOS software, the CLI required prior knowledge of
the TCP ports for which the reservation was being made. Because DLSw+ uses one well-known port
and one randomly assigned port, the reservation could not be made until after the peer connection was
active.
The DLSw+ RSVP feature permits new DLSw+ peer connections to automatically request bandwidth
reservations upon connection, thereby removing the need for user intervention after the peer is
connected. This feature assures the reservation will survive a network or device failure and that the
DLSw+ traffic carried over a TCP connection is not affected by congestion.
Fancy Queuing on Frame Relay for Cisco HDLC
In previous releases, when the voice-encap option was configured on Frame Relay or Cisco HDLC, all
fancy queuing (such as weighted fair queuing, custom queuing, and priority queuing) on the interface
was disabled, and queuing was handled on a first-come first-served (FCFS) basis. In this release, new
enhancements have been made to support fancy queuing on Frame Relay and Cisco HDLC.