Nortel Networks WEB OS 212777 - Manual (Page 453)

Web OS 10.0 Application Guide
Chapter 17: Bandwidth Management n 453
212777-A, February 2002
Packet Coloring (TOS bits) for Burst Limit
Whenever the soft limit is exceeded, optional packet coloring can be done to allow down-
stream routers to use diff-serv mechanisms (that is, writing the Type-Of-Service (TOS) byte of
the IP header) to delay or discard these out-of-profile frames. Frames that are not out-of -pro-
file are marked with a different, higher priority value. This feature can be enabled or disabled
on a per-contract basis, using the
wtos option under the contract menu ( /cfg/bwm/cont
x/wtos) to enable/disable overwriting IP TOS.
The actual values used by the switch for overwriting TOS values (depending on whether traffic
is over or under the soft TOS limit) are set in the bandwidth policy menu (
/cfg/bwm/pol
x) with the utos and otos options. The values allowed are 0-255. Typically, the values spec-
ified should match the appropriate diff-serv specification but could be different, depend-
ing on the customer environment.
Operational Keys
There are two operational keys for BWM: a standard key and a demo key. The demo key auto-
matically expires after a demo time period. These keys may only be enabled if Layer 4 services
have been enabled.