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
Currently, IP and IPX extended access lists are the only functions that can use time ranges. The time
range allows the network administrator to define when the permit or deny statements in the access list
are in effect. Prior to this feature, access list statements were always in effect once they were applied.
Both named or numbered access lists can reference a time range.
RIP Enhancements
Triggered extensions to IP RIP increase efficiency of RIP on point-to-point, serial interfaces.
Routers are used on connection-oriented networks to allow potential connectivity to many remote
destinations. Circuits on the WAN are established on demand and are relinquished when the traffic
subsides. Depending on the application, the connection between any two sites for user data could be
short and relatively infrequent.
There were two problems using RIP to connect to a WAN:
• Periodic broadcasting by RIP generally prevented WAN circuits form being closed.
• Even on fixed, point-to-point links, the overhead of periodic RIP transmissions could seriously
interrupt normal data transfer because of the quantity of information that hits the line every 30
seconds.
To overcome these limitations, triggered extensions to RIP cause RIP to send information on the WAN
only when there has been an update to the routing database. Periodic update packets are suppressed over
the interface on which this feature is enabled.
Cisco IOS Firewall Feature Set Platform Support
The Cisco IOS Firewall feature set is now available on 2600 and 3600 series products.
The Cisco IOS Firewall feature set extends the security technology currently available in Cisco IOS
software to provide firewall specific capabilities:
• Context-based Access Control (CBAC)
• Java blocking
• Denial-of-service detection and prevention
• Real-time alerts and audit trails
The Cisco IOS Firewall feature set adds advanced filtering capabilities to existing security functionality
in Cisco routers. Some existing Cisco IOS security features include packet filtering via access control
lists (ACLs), Network Address Translation (NAT), network-layer encryption, and TACACS+
authentication.
ISDN MIB RFC2127
The new Integrated Services Digital Network (ISDN) Management Information Base (MIB) RFC2127
has been designed to provide useful information in accordance with the IETF’s new standard for the
management of ISDN interfaces. It controls all aspects of ISDN interfaces. RFC2127 provides
information on the physical Basic Rate Interfaces (BRIs), control and statistical information for B
(bearer) and D (signaling) channels, terminal endpoints, and directory numbers.