Re: MPLS Aggregate label

Imp null label is given to connected and summarized prefixes on egress side

If this was nt thr thne egress LSR have to double lookup.. First to look abt label in lfib n then learn tht it needs to be removed..thn ip lookup

Thrfore solution is to have egress LSR signal last but one LSR in LSP to send packets without label, tells second last LSR to use implicit null by nt sending regular label

Result is tht egress lsr sees ip packet and performs ip lookup

Its simply called a pop label

HTH
Cheers!!
Raghava

Sent from my BlackBerry. Vodafone.

-----Original Message-----
From: "Aaron" <aaron1_at_gvtc.com>
Sender: nobody_at_groupstudy.com
Date: Wed, 9 Mar 2011 14:44:27
To: 'CCIE KID'<eliteccie_at_gmail.com>; 'Cisco certification'<ccielab_at_groupstudy.com>
Reply-To: "Aaron" <aaron1_at_gvtc.com>
Subject: RE: MPLS Aggregate label

Just saw this in my lab today... imp-null seems to have some correlation to
connected routes.... perhaps someone can shed some light on this
fact/observation...

R6#sh mpls ip binding
  10.10.10.0/24
        in label: imp-null
  140.100.0.0/27
        in label: 24
  140.100.0.32/27
        in label: 23
  140.100.0.64/28
        in label: 20
  140.100.0.84/30
        in label: 22
  140.100.0.88/30
        in label: 21
  140.100.1.0/24
        in label: 25
  140.100.2.0/24
        in label: imp-null
  140.100.3.0/24
        in label: imp-null
  151.100.0.0/15
        in label: 34
  172.16.0.0/16
        in label: 26
  192.128.128.0/24
        in label: 19
  199.199.1.0/24
        in label: 29
  199.199.2.0/24
        in label: 28
  199.199.3.0/24
        in label: 27
  199.199.4.0/24
        in label: 33
  199.199.5.0/24
        in label: 32
  199.199.6.0/24
        in label: 31
  199.199.7.0/24
        in label: 30
  199.199.8.0/24
        in label: 18
  199.199.9.0/24
        in label: 17
  199.199.10.0/24
        in label: 16
R6#
R6#
R6#
R6#sh ip ro con
R6#sh ip ro connected
     140.100.0.0/16 is variably subnetted, 8 subnets, 4 masks
C 140.100.2.0/24 is directly connected, FastEthernet0/0
C 140.100.3.0/24 is directly connected, FastEthernet0/1
     10.0.0.0/24 is subnetted, 1 subnets
C 10.10.10.0 is directly connected, Ethernet4/0
R6#

-----Original Message-----
From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of CCIE
KID
Sent: Wednesday, March 09, 2011 5:18 AM
To: Cisco certification
Subject: MPLS Aggregate label

Hey what is the difference between Aggregate label ,implicit null and
explicit null label in MPLS

-- 
With Warmest Regards,
CCIE KID
IN PURSUIT OF CCIE
Blogs and organic groups at http://www.ccie.net