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1 summary of path, 2 automatic summarization of path, Summary of path – Siemens S223 User Manual

Page 320: Automatic summarization of path

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UMN:CLI User Manual

SURPASS hiD 6615 S223/S323 R1.5

320 A50010-Y3-C150-2-7619

10.1.2.1

Summary of Path

Aggregation combines the characteristics of several different routes and advertises a sin-
gle route. In the example of 2 routes information of 172.16.0.0/24 and 172.16.1.0/24, the
as-set

parameter creates an aggregate entry advertising the path for a single route of

172.16.0.0/23, consisting of all elements contained in all paths being summarized. Use
this feature to reduce the size of path information by listing the AS number only once,
even if it was included in multiple paths that were aggregated. And it’s useful when ag-
gregation of information results in incomplete path information.

Using the summary-only parameter transmits the IP prefix only, suppressing the more-
specific routes to all neighbors. Using the as-set parameter transmits a single AS path in-
formation only, one of AS numbers of each path.

To summarize route’s information for the transmission, use the following command.

Command Mode

Description

aggregate-address

A.B.C.D/M

as-set

[summary-only]

aggregate-address

A.B.C.D/M

summary-only

[as-set]

Router

Summarizes the information of routes and transmits it
to the other routers.
A.B.C.D/M: network address
summary-only: transmits IP prefix only.
as-set: transmits one AS-path information.

To delete the route’s information of specific network address, use the following command.

Command Mode

Description

no aggregate-address A.B.C.D/M

as-set

[summary-only]

no aggregate-address A.B.C.D/M

summary-only

[as-set]

Router

Disables the summarization function of routes.

10.1.2.2

Automatic Summarization of Path

Automatic summarization is new feature to expend the route information up to the class of
specified IP address on interface connected directly to BGP router. For example, A class
is fundamentally had “/8” as the subnet mask in case IP address assigned 100.1.1.1 in A
class. It can generate route information of 100.0.0.0/8.

To enable/disable automatic summarization of the route, use the following command.

Command Mode

Description

auto-summary

Enables automatic network summarization of a route.

no auto-summary

Router

Disables automatic network summarization of a route.

Please note that, use this feature when you use the basic classes in network.

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