Diff-Serv Traffic Engineering
Page 114 7450 ESS MPLS Guide
Diff-Serv TE Configuration and Operation
RSVP Protocol Level
The following are the configuration steps at the RSVP protocol level:
1. The operator enables Diff-Serv TE by executing the diffserv-te command in the
config>router>rsvp context. When this command is enabled, IS-IS and OSPF will start
advertising available bandwidth for each TE class configured under the diffserv-te node.
The operator can disable Diff-Serv TE globally by using the no form of the command.
2. The enabling or disabling of Diff-Serv on the system requires that the RSVP and MPLS
protocol be shutdown. The operator must execute the no shutdown command in each
context once all parameters under both protocols are defined. When saved in the
configuration file, the no shutdown command is automatically inserted under both
protocols to make sure they come up after a node reboot.
3. IGP will advertise the available bandwidth in each TE class in the unreserved bandwidth
TE parameter for that class for each RSVP interface in the system.
4. In addition, IGP will continue to advertise the existing Maximum Reservable Link
Bandwidth TE parameter so the maximum bandwidth that can be booked on a given
interface by all classes. The value advertised is adjusted with the link subscription factor
configured in the config>router>rsvp>interface>subscription percentage context.
5. The operator can overbook (underbook) the maximum reservable bandwidth of a given
CT by overbooking (underbooking) the interface maximum reservable bandwidth by
configuring the appropriate value for the subscription percentage parameter.
6. The diffserv-te command will only have effect if the operator has already enabled traffic
engineering at the IS-IS and/or OSPF routing protocol levels:
config>router>isis>traffic-engineering
and/or:
config>router>ospf>traffic-engineering
7. The following Diff-Serv TE parameters are configured globally under the diffserv-te
node. They apply to all RSVP interfaces on the system. Once configured, these parameters
can only be changed after shutting down the MPLS and RSVP protocols:
a. Definition of TE classes, TE Class = {Class Type (CT), LSP priority}. Eight TE classes
can be supported. There is no default TE class once Diff-Serv is enabled. The operator
must explicitly define each TE class. However, when Diff-Serv is disabled there will be an
internal use of the default CT (CT0) and eight pre-emption priorities as shown in Table 5.
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