Accumulated Interior Gateway Protocol Attribute; Originate Prefixes With Aigp - Cisco NCS 5500 Series Configuration Manual

Accumulated Interior Gateway Protocol Attribute

Specifies the BGP AS number, and enters the BGP configuration mode, for configuring BGP routing processes.
Step 3 no nsr disable
Example:
RP/0/RP0/CPU0:router(config-bgp)# nsr disable
Enables BGP Nonstop routing.
Step 4 commit
Re-enable BGP Nonstop Routing: Example
The following example shows how to enable BGP NSR:
configure
router bgp 120
nsr
end
Accumulated Interior Gateway Protocol Attribute
The Accumulated Interior Gateway Protocol (AiGP)Attribute is an optional non-transitive BGP Path Attribute.
The attribute type code for the AiGP Attribute is to be assigned by IANA. The value field of the AiGP Attribute
is defined as a set of Type/Length/Value elements (TLVs). The AiGP TLV contains the Accumulated IGP
Metric.
The AiGP feature is required in the 3107 network to simulate the current OSPF behavior of computing the
distance associated with a path. OSPF/LDP carries the prefix/label information only in the local area. Then,
BGP carries the prefix/lable to all the remote areas by redistributing the routes into BGP at area boundaries.
The routes/labels are then advertised using LSPs. The next hop for the route is changed at each ABR to local
router which removes the need to leak OSPF routes across area boundaries. The bandwidth available on each
of the core links is mapped to OSPF cost, hence it is imperative that BGP carries this cost correctly between
each of the PEs. This functionality is achieved by using the AiGP.

Originate Prefixes with AiGP

Perform this task to configure origination of routes with the AiGP metric:
Before You Begin
Origination of routes with the accumulated interior gateway protocol (AiGP) metric is controlled by
configuration. AiGP attributes are attached to redistributed routes that satisfy following conditions:
• The protocol redistributing the route is enabled for AiGP.
• The route is an interior gateway protocol (iGP) route redistributed into border gateway protocol (BGP).
BGP Configuration Guide for Cisco NCS 5500 Series Routers, IOS XR Release 6.2.x
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The value assigned to the AiGP attribute is the value of iGP next hop to the route or as set by a
route-policy.
Implementing BGP