Specifications

60
Release Notes for Cisco 7000 Family for Cisco IOS Release 12.1 T
78-10811-05
New and Changed Information
The RSVP support for Frame Relay feature allows RSVP to work with per VC (data link connection
identifier (DLCI)) queueing for voice-like flows. Traffic shaping must be enabled in a Frame Relay
environment for accurate admission control of resources (bandwidth and queues) at the congestion
point; that is, the VC itself. Specifically, RSVP can work with VCs defined at the interface and
subinterface levels. There is no limit to the number of VCs that can be configured per interface or
subinterface.
SDLC SNRM Timer and Window Size Enhancements
Platforms: Cisco 7100 series, Cisco 7200 series, and Cisco 7500 series routers
The SDLC SNRM Timer and Window Size Enhancements feature introduces a new window size setting
for SDLC configurations, and a new timeout setting for the SNRM frame. These enhancements change
the operation of SDLC processing on a multidrop line.
Window Size Setting
Prior to this feature, all SDLC addresses on the multidrop had the same window count. Now the window
count can be configured on a Physical Unit (PU) or SDLC address level. This enhancement gives a
controller a different window size than other devices on the interface, and allows devices attached to
the multidrop to be sized individually.
Timeout Setting for SNRM Frame
Cisco IOS software SDLC implementation currently utilizes a common response timer (T1) for all
outstanding commands. Calculating the maximum frame size and line speed produces a minimum time
of 3.5 seconds for receiving acknowledgments; thus, polling stations used for link activation utilize this
3.5-second timer. This is a problem on a multidrop, because stations that do not respond to the SNRM
will have 3.5 seconds of downtime-waiting before the next station that is active is polled. This
enhancement reduces the time to stations that are waiting idle, as opposed to those that are active.
Set ATM CLP Bit
Platforms: Cisco 7100 series, Cisco 7200 series, and Cisco 7500 series routers
The Cell Lost Priority (CLP) bit in the ATM header of a cell provides a method of controlling the
discarding of cells in a congested ATM environment. A CLP bit contains two settings: 0 or 1. Cells with
a CLP bit setting of 1 are discarded before cells with a CLP bit setting of 0.
Before the introduction of the ATM CLP Setting feature, the CLP bit was automatically set to 0 when
Cisco routers converted packets into ATM cells for ATM networks.
The ATM CLP Setting feature allows users to control the CLP bit setting on routers with the PA-A3 port
adapter. The CLP bit is set on each packet individually, and the default CLP bit setting is 0. The
application of the ATM CLP Setting feature changes the CLP bit setting to 1. Therefore, users have the
option to leave each packet with the default CLP bit setting of 0 or to establish a new CLP bit setting
of 1.
ATM CLP Setting is documented as part of the Class-Based Packet Marking feature.