Specifications

52
Release Notes for Cisco 7000 Family for Cisco IOS Release 12.1 T
78-10811-05
New and Changed Information
Distributed Traffic Shaping
Platforms: Cisco 7500 series routers
The DTS feature is one element used to manage the bandwidth of an interface to avoid congestion, to
meet remote site requirements, and to conform to a service rate that is provided on that interface.
DTS uses queues to buffer traffic surges that can congest a network. Data is buffered and then sent into
the network at a regulated rate. This ensures that traffic will behave to the configured descriptor, as
defined by command information rate (CIR), Committed Burst (Bc), and Excess Burst (Be). With the
defined average bit rate and burst size that is acceptable on that shaped entity, you can derive a time
interval value.
DTS provides two types of shape commands: average and peak. When shape average is configured, the
interface sends no more than the Bc for each interval, achieving an average rate no higher than the CIR.
When shape peak is configured, the interface sends Bc plus Be bits in each interval.
In a link layer network such as Frame Relay, the network sends messages with the forward explicit
congestion notification (FECN) or backwards explicit congestion notification (BECN) if there is
congestion. With the DTS feature, the traffic shaping adaptive mode takes advantage of these signals
and adjusts the traffic descriptors. This approximates the rate to the available bandwidth along the path.
For additional information on Distributed Traffic Shaping, see the Distributed Traffic Shaping feature
module on Cisco.com and the Documentation CD-ROM.
FastEther Channel Enhancements on Cisco 7200 Series Routers
Platforms: Cisco 7200 series routers
FastEther Channel provides higher bidirectional bandwidth, redundancy, and load sharing. Up to four
Fast Ethernet interfaces can be bundled in a port-channel, and the router or switch can support up to
four port-channels. The FastEther Channel feature is capable of load balancing traffic across the Fast
Ethernet links. Unicast, broadcast, and multicast traffic is distributed across the links providing higher
performance and redundant parallel paths. In the event of a link failure, traffic is redirected to remaining
links within the FastEther Channel without user intervention.
In this release of the FastEther Channel feature, IP traffic is distributed over the port-channel interface
while traffic from other routing protocols is sent over a single link. Bridged traffic is distributed based
on the Layer 3 information in the packet. If the Layer 3 information does not exist in the packet, the
traffic is sent over the first link.
FastEther Channel supports all features currently supported on the Fast Ethernet interface. You must
configure these features on the port-channel interface rather than on the individual Fast Ethernet
interfaces. FastEther Channel connections are fully compatible with Cisco IOS virtual LAN (VLAN)
and routing technologies. The Inter-Switch Link (ISL) VLAN trunking protocol can carry multiple
VLANs across a FastEther Channel, and routers attached to FastEther Channel links can provide full
multiprotocol routing with support for host standby using Host Standby Router Protocol (HSRP).
The port-channel (consisting of up to four Fast Ethernet interfaces) is treated as a single interface.
Port-channel is used in the Cisco IOS software to maintain compatibility with existing commands on
the Catalyst 5000 switch. You create the FastEther Channel by using the interface port-channel
interface configuration command. You can assign up to four Fast Ethernet interfaces to a port-channel
by using the channel-group interface configuration command