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Beginner

MPLS VPN - Set Weight Based on Route Distinguisher

Hi,

I try to match the route learned with RD 10081:84 , and then set the weight to 100.

I can't find the keyword RD at ip extcommunity-list, only SOO and RT.

Can guide is there other way to perform it ?

What I try to achive is to manipulate the  weight of route learn from PE with RD 10081:84

ip extcommunity-list 10 permit soo 10081:84

route-map gngp permit 10

match extcommunity 10

set weight 100

router bgp 10081

o synchronization

bgp router-id 172.18.255.16

bgp log-neighbor-changes

neighbor 172.18.255.250 remote-as 10081

neighbor 172.18.255.250 update-source Loopback0

no auto-summary

!

address-family vpnv4

  neighbor 172.18.255.250 activate

  neighbor 172.18.255.250 send-community both

  neighbor 172.18.255.250 route-map gngp in

exit-address-family

KKBPE2#sh bgp vpnv4 unicast rd 10081:84
BGP table version is 104, local router ID is 172.18.255.16
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
Route Distinguisher: 10081:84
*>i172.18.188.0/24  172.18.255.202           0    100      0 ?

8 REPLIES 8
Cisco Employee

MPLS VPN - Set Weight Based on Route Distinguisher

Hi,

RD is not ext community and to my knowledge cannot be used to match to set any attributes. You may have to use RT to perform the same.

HTH,

Nagendra

Hall of Fame Expert

MPLS VPN - Set Weight Based on Route Distinguisher

Hello tckoon@hp,

Nagendra is right:   a route distinguisher is not an extended community of type Site of origin, RD is the first 64 bits of the vpnv4 prefix.

you should set an extended community of type SOO on remote PE node and then you will be able to match on it

Hope to help

Giuseppe

Beginner

MPLS VPN - Set Weight Based on Route Distinguisher

SOO is not support for outbound.

Managed to use standard BGP community to achieve it.

Regards

Beginner

MPLS VPN - Set Weight Based on Route Distinguisher

tckoon@hp wrote:

SOO is not support for outbound.

Managed to use standard BGP community to achieve it.

Regards

Yeah it is....

Example configuration:

ip prefix-list NET66 permit 172.10.66.0/24

!

route-map SOO_OUT permit 10

  match ip address prefix-list NET66

  set extcommunity soo 1000:66

!

int Fa1/0.66

ip vrf sitemap SOO_OUT

!

Cheers,

Joe.

Highlighted
Beginner

MPLS VPN - Set Weight Based on Route Distinguisher

Not for BGP peering.

neighbor x.x.x.x route-map SOO_OUT out.

The IOS will complaint , only support IN , not OUT

Regards

Re: MPLS VPN - Set Weight Based on Route Distinguisher

alternatively as mentioned above use RT instead of RD

for example

ip extcommunity-list standard PreferredRT permit rt 10081:84

this will help you to match on route targets attached to incoming VPNv4 BGP updates and use them to modify the BGP attribute of that route

then you can match it with your inbound route-map

but make sure the PE in the other end sending RT of 10081:84 associated with that route

HTH

Beginner

Re: MPLS VPN - Set Weight Based on Route Distinguisher

Yes it is because RD is jusr to the local router it is not advertised in bgp or bgp at all, you need use the RT

Domingues

CCIE RS # 29765

Sent from Cisco Technical Support iPad

MPLS VPN - Set Weight Based on Route Distinguisher

Hi Domingues

RD is not only locally significant with MPBGP and L3VPNs

MPLS-based VPNs employ BGP to communicate between PEs to facilitate customer routes. This is made possible through extensions to BGP that carry addresses other than IPv4 addresses. A notable extension is called the route distinguisher (RD).

The purpose of the route distinguisher (RD) is to make the prefix value unique across the backbone. Prefixes should use the same RD if they are associated with the same set of route targets (RTs) and anything else that is used to select routing policy.

http://www.cisco.com/en/US/docs/net_mgmt/vpn_solutions_center/1.1/user/guide/VPN_UG1.html#wp1019044

RDs allow BGP to advertise and distinguish between duplicate IPv4 prefixes. The concept is simple: advertise each NLRI (prefix) as the traditional IPv4 prefix, but add another number (the RD) that uniquely identifies the route. In particular, the new NLRI format, called VPN-V4, has the following two parts:

  • A 64-bit RD
  • A 32-bit IPv4 prefix

http://www.ciscopress.com/articles/article.asp?p=1081501&seqNum=4

HTH

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