Hi, Thanks for looking into, however, I am not sure if i understand it completly. My question is For what routes will a PE advertise an IMPLICIT NULL label? I know it does advertises Implicit null (LDP value 3 or TDP Value 1) for prefixes that need an IP lookup on the PE itslef. The only route types that come to my mind are route 'Connected'on PE & Routes 'Aggregated'for PE. By the way a router will generate a MPLS label for every prefix installed in RIB via IGP. This I beleive has nothing to do with implicit null. For Example: R3----mpls----R1---R2 (2.2.2.2) | | (3.3.3.3) (1.1.1.1) MPLS is not enabled on the link between R1 & R2 & OSPF is the configured IGP. R1 learns about 2.2.2.2 via OSPF R1#sh ip route ospf 2.0.0.0/32 is subnetted, 1 subnets O 2.2.2.2 [110/11] via 12.0.0.2, 00:20:44, FastEthernet0/0 3.0.0.0/32 is subnetted, 1 subnets O 3.3.3.3 [110/11] via 13.0.0.3, 00:20:13, FastEthernet0/1
Although MPLS is not enabled between R1 & R2, however, R1 still genarates & advertises a label to R3 (100 in this case). R1#sh mpls forwarding-table Local Outgoing Prefix Bytes tag Outgoing Next Hop tag tag or VC or Tunnel Id switched interface 100 Untagged 2.2.2.2/32 0 Fa0/0 12.0.0.2 101 Pop tag 3.3.3.3/32 0 Fa0/1 13.0.0.3 R1 advertises this to R3 & R3 uses 100 as otugoing label: R3#sh mpls forwarding-table Local Outgoing Prefix Bytes tag Outgoing Next Hop tag tag or VC or Tunnel Id switched interface 300 100 2.2.2.2/32 0 Fa0/0 13.0.0.1 301 Pop tag 1.1.1.1/32 0 Fa0/0 13.0.0.1 So the question remains, is there a scenario in IPv4 or VPNv4 when an EDGE router will advertise an Implicit label aprt for connected & aggregated routes? Thank You. ________________________________ From: Nicola Arnoldi <[email protected]> To: Narendra Naukwal <[email protected]> Cc: "[email protected]" <[email protected]> Sent: Sunday, 7 April 2013 7:10 PM Subject: Re: [OSL | CCIE_RS] MPLS - PHP It is used as well for every route the Edge LSR learns from a PE to CE routing protocol. No MPLS=PHP. On Sun, Apr 7, 2013 at 8:16 AM, Narendra Naukwal <[email protected]> wrote: Experts, > >Is there a scenario wherein an Edge LSR signals an Implicit Null label to its >directly connected Upstream neighbor for a subnet other which is not Connected >or Summarized on the Edge LSR? > >Thank You. >Naren >_______________________________________________ >For more information regarding industry leading CCIE Lab training, please >visit http://www.ipexpert.com/ > >Are you a CCNP or CCIE and looking for a job? Check out >http://www.platinumplacement.com/ > >http://onlinestudylist.com/mailman/listinfo/ccie_rs > _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com Are you a CCNP or CCIE and looking for a job? Check out www.PlatinumPlacement.com http://onlinestudylist.com/mailman/listinfo/ccie_rs
