User guide

33
Release Notes for Cisco 2500 Series for Cisco IOS Release 12.0 T
78-5563-07 Rev.H0
New and Changed Information
The RSM module can either route or bridge Token Ring packets, thereby functioning as a router or as
a bridge. In Cisco IOS Release 12.0(1)T, both APPN and DLSW+ are supported on the RSM's Token
Ring VLANs. RSRB, however, is not supported on the RSM.
Mobile IP
Mobile IP provides users the freedom to roam beyond their home subnet while consistently maintaining
their home IP address. This enables transparent routing of IP datagrams to mobile users during their
movement, so that data sessions can be initiated to them while they roam; it also enables sessions to be
maintained in spite of physical movement between points of attachment to the Internet or other
networks. Cisco’s implementation of Mobile IP is fully compliant with the Internet Engineering Task
Force’s (IETF’s) proposed standard defined in Request for Comments (RFC) 2002.
Easy IP Phase 2-DHCP Server
With the introduction of Easy IP Phase 2, Cisco IOS software also supports Intelligent DHCP Relay
functionality. A DHCP Relay Agent is any host that forwards DHCP packets between clients and
servers. A DHCP Relay Agent enables the client and server to reside on separate subnets. If the Cisco
IOS DHCP server cannot satisfy a DHCP request from its own database, it can forward the DHCP
request to one or more secondary DHCP servers defined by the network administrator using standard
Cisco IOS ip helper-address functionality.
Smart-init (Mars FE2P)
The smart-init feature is an extension to the existing memory split program of the Cisco IOS software
running on Cisco 3600 series routers. It computes iomem size by looking at the network modules
installed in the system and uses this iomem for carrying out the memory split. Also, compatibility with
older IOS configurations is maintained by retaining support for the memory-size configuration
command. The user can disable smart-init and set iomem percentage to the required value by issuing
the memory-size configuration command.
OSPF Packet Pacing
The former OSPF implementation for sending update packets needed to be more efficient. Some update
packets were getting lost in cases where the link was slow, a neighbor could not receive the updates fast
enough, or the router was out of buffer space. For example, packets might be dropped if either of these
topologies existed:
• A fast router was connected to a slower router over a point-to-point link.
• During flooding, several neighbors dumped updates to a single router at the same time.
OSPF update packets are now automatically paced by a delay of 33 milliseconds. Pacing is also added
between retransmissions to increase efficiency and minimize lost retransmissions.
OSPF update and retransmission packets are sent more efficiently. Also, you can display the LSAs
waiting to be sent out an interface.
Time-Based Access Lists
It is now possible to implement access lists based on the time of day. To do so, you create a time range
that defines specific times of the day and week. The time range is identified by a name, and then
referenced by a function, so that those time restrictions are imposed on the function itself.