Preserving Redirect Nexthop - Cisco ASR 9000 Series Routing Configuration Manual

Implementing BGP Flowspec
Command or Action
Received Path ID 0, Local Path ID 1, version 42
Extended community: FLOWSPEC Traffic-rate:100,0
Step 5
show pbr-pal ipolicy all locationnode-id

Preserving Redirect Nexthop

You can explicitly configure redirect nexthop as part of the route specification. Redirect nexthop is encoded
as the MP_REACH nexthop in the BGP flowspec NLRI along with the associated extended community.
Recipient of such a flowspec route redirects traffic as per FIB lookup for the redirect nexthop, the nexthop
can possibly resolve over IP or MPLS tunnel. As the MP_REACH nexthop can be overwritten at a eBGP
boundary, for cases where the nexthop connectivity spans multiple AS's, the nexthop can be preserved through
the use of the unchanged knob.
SUMMARY STEPS
1. configure
2. router bgp as-number
3. neighbor ip-address
4. address-family { ipv4 }
5. flowspec next-hop unchanged
DETAILED STEPS
Command or Action
Step 1 configure
Step 2 router bgp as-number
Example:
RP/0/RSP0/CPU0:router(config)# router bgp 100
Step 3 neighbor ip-address
Example:
RP/0/RSP0/CPU0:router(config)# router bgp 100
neighbor 1.1.1.1
Cisco ASR 9000 Series Aggregation Services Router Routing Configuration Guide, Release 5.3.x
Preserving Redirect Nexthop
Purpose
In this example, the action defined
is to rate limit the traffic.
On platform dependent devices,
use this command to verify if a
flowspec rule configured on the
controller router is available on the
BGP side.
Purpose
Specifies the autonomous system number and enters the
BGP configuration mode, allowing you to configure the
BGP routing process.
Places the router in neighbor configuration mode for BGP
routing and configures the neighbor IP address as a BGP
peer.
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