Chapter 16: Dynamic Routing Protocols
STANDARD Revision 1.0 C4® CMTS Release 8.3 User Guide
© 2016 ARRIS Enterprises LLC. All Rights Reserved. 533
The command filters routes that are redistributed from various routing protocols (such as static, connected, ISIS, OSPF and
RIPv2) into BGP IPv4 AF.
Route Redistribution Filtering
MIB support built into the routing protocol software allows for the following BGP filtering to be used for route
redistribution (in addition to destination IP address filtering):
Next-Hop — Allows route redistribution to be controlled based on the advertising router (next-hop). May also be used
with other routing protocols
BGP Community Number (match or set) — 4 byte value identifying a BGP community
BGP Extended Community Number (match or set) — 8 byte value identifying a BGP community
BGP Origin (set) — Allows the origin attribute to be set for routes redistributed into BGP
Multi-Exist-Discriminator (set) — Allows a MED attribute value to be set for routes redistributed into BGP.
Local Pref — Allows a Local Preference attribute to be set for routes redistributed into BGP.
Update Message Attributes
The attributes that are applied to the complete group of routes in the BGP Update message are listed as follows:
Origin — Indicates how the IP prefixes became known to BGP.
IGP — Prefix was learned from an interior gateway protocol (e.g. OSPF).
EGP — Prefix was learned via EGP.
Incomplete — Protocol was learned from a source other than IGP/EGP. For example, static or local routes.
AS-Path — A list of ASs the group of routes has passed through.
Next-Hop — Identifies the next hop for the group of routes. This could be a third-party next-hop.
Multi-Exit-Discriminator — Allows for choosing the optimal link for a group of routes when more than one connection
exists between two ASs.
Local-Pref — Allows for choosing the optimal link for a group of routes when multiple connections exists to different
intermediate ASs.
Aggregator — Identifies the AS that performed route aggregation.
Communities — Ability to associate a unique identifier with a route. The following well-known communities are
supported:
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