Specifications

Table Of Contents
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Release Notes for Cisco 7000 Family for Cisco IOS Release 12.1 T
78-10811-05
New and Changed Information
Turbo Access Control Lists
Platforms: Cisco 7200 series routers
Access control lists (ACLs) are normally searched sequentially to find a matching rule, and ACLs are
ordered specifically to take this factor into account. Because of the increasing needs and requirements
for security filtering and packet classification, ACLs can expand to the point that searching the ACL
adds a significant amount of time and memory when packets are being forwarded. Moreover, the time
taken by the router to search the list is not always consistent, adding a variable latency to the packet
forwarding. A high CPU load is necessary for searching an ACL with several entries.
The Turbo ACL feature compiles the ACLs into a set of lookup tables, while maintaining the first match
requirements. Packet headers are used to access these tables in a small, fixed number of lookups,
independently of the existing number of ACL entries. The benefits of this feature include:
For ACLs larger than 3 entries, the CPU load required to match the packet to the pre-determined
packet-matching rule is lessened. The CPU load is fixed, regardless of the size of the ACL, allowing
for larger ACLs without incurring any CPU overhead penalties. The larger the ACL, the greater the
benefit.
The time taken to match the packet is fixed, so that latency of the packets are smaller (significantly
in the case of large ACLs) and more importantly, consistent, allowing better network stability and
more accurate transit times.
For additional information on the Turbo ACL feature, see the Turbo Access Control Lists feature
module on Cisco.com and the Documentation CD-ROM.
VIP-Based Distributed FRF.11/12
Platforms: Cisco 7500 series routers
The Voice Over Frame Relay using FRF.11 and FRF.12 capabilities currently available in Cisco IOS
Release 12.1 T are now available, with some modifications, on VIP-enabled Cisco 7500 series routers.
The new feature is called VIP-Based Distributed FRF.11 and FRF.12 (VIP-Based FRF.11 and FRF.12).
For additional information on VIP-Based FRF.11 and FRF.12, see the Versatile Interface
Processor-Based Distributed FRF.11 and FRF.12 feature module on Cisco.com and the Documentation
CD-ROM.
VIP-Based WFQ Support for RSVP
Platforms: Cisco 7500 series routers
In earlier software releases, Resource Reservation Protocol (RSVP) on Cisco 7500 series routers would
leverage Route Switch Processor-based (RSP-based) weighted fair-queuing to guarantee bandwidth to
RSVP flows.
RSVP now interoperates with distributed weighted fair-queuing (dWFQ), thus offloading the RSP of
the overhead of the queueing function and improving RSVP scalability. RSVP support of dWFQ is
transparent to the user.