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I'm working on my ISCW certification.

can someone please explain the following config:

ip vrf vrf2

     rd 100:2

     route-target both 100:2

     route-target import 100:1

     import map vrf2_import


I'm a bit lost with the 100:2 and 100:1 parameters, do not recall reading about it in my books...

Correct Answer by Giuseppe Larosa about 7 years 6 months ago

Hello Ofir,


>> I'm a bit lost with the 100:2 and 100:1 parameters, do not recall reading about it in my books..


they are chosen in network design. possible notations are:

ASN:value

or

PE-loop-ipaddr:value.

They are 64 bits integers


Focus on concepts:

this is a VRF site, using Route Distinguisher 100:2

exporting VRF routes in VPNv4 advsertisements with route-target attribute 100:2

>> route-target both 100:2 =

route-target import 100:2

route-target export 100:2


importing in VRF from backbone all VPNv4 routes that have RT= 100:1 or RT=100:2 or at least one of RT values is 100:1 or 100:2


VPNv4 route is created by prefixing 64 bit RD to IPv4 32 bit. RD is used to support address overlapping.


RT is an extended community attribute that provides "colors" to the routes.

(Each route can have one or more RT values associated it is not limited to only one)


Each VRF site is configured to import from backbone one or more RT values and to export local VRF routes to backbone with one or more RT values.


In case of your configuration the import phase from backbone uses an additional filter that is a route map named vrf2_import.


As a result  of this only VPNv4 routes with have one RT =100:1 or Rt=100:2 and that are permitted by route-map vrf2_import are installed in vrf2 routing table on local PE node.


Hope to help

Giuseppe

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Jon Marshall Wed, 01/20/2010 - 06:48
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[email protected] wrote:


I'm working on my ISCW certification.

can someone please explain the following config:

ip vrf vrf2

     rd 100:2

     route-target both 100:2

     route-target import 100:1

     import map vrf2_import


I'm a bit lost with the 100:2 and 100:1 parameters, do not recall reading about it in my books...


Have a look at this thread which explains what they do -


https://supportforums.cisco.com/message/764768#764768


Jon

Correct Answer
Giuseppe Larosa Wed, 01/20/2010 - 08:02
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  • Super Silver, 17500 points or more
  • Hall of Fame,

    Founding Member

Hello Ofir,


>> I'm a bit lost with the 100:2 and 100:1 parameters, do not recall reading about it in my books..


they are chosen in network design. possible notations are:

ASN:value

or

PE-loop-ipaddr:value.

They are 64 bits integers


Focus on concepts:

this is a VRF site, using Route Distinguisher 100:2

exporting VRF routes in VPNv4 advsertisements with route-target attribute 100:2

>> route-target both 100:2 =

route-target import 100:2

route-target export 100:2


importing in VRF from backbone all VPNv4 routes that have RT= 100:1 or RT=100:2 or at least one of RT values is 100:1 or 100:2


VPNv4 route is created by prefixing 64 bit RD to IPv4 32 bit. RD is used to support address overlapping.


RT is an extended community attribute that provides "colors" to the routes.

(Each route can have one or more RT values associated it is not limited to only one)


Each VRF site is configured to import from backbone one or more RT values and to export local VRF routes to backbone with one or more RT values.


In case of your configuration the import phase from backbone uses an additional filter that is a route map named vrf2_import.


As a result  of this only VPNv4 routes with have one RT =100:1 or Rt=100:2 and that are permitted by route-map vrf2_import are installed in vrf2 routing table on local PE node.


Hope to help

Giuseppe

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