You may find these useful:
http://tools.ietf.org/html/rfc3032
http://www.cisco.com/en/US/tech/tk436/tk428/technologies_q_and_a_item09186a00800949e5.shtml#q13
-- Regards, Elias CCIE#17354 On 26 December 2010 19:22, Carlos G Mendioroz <tron_at_huapi.ba.ar> wrote: > Hmm, no. > Explicit-null would actually use the null (0) tag on the last MPLS hop. > Explicit-null will just show as 0, AFAIK. > > -Carlos > > George Goglidze wrote: >> >> I can't check it right now, but I think "explicit-null" label would >> indicate "Untagged" as well in the LFIB. >> Please correct me if I'm wrong. >> >> Regards, >> >> On Sun, Dec 26, 2010 at 2:05 PM, Carlos G Mendioroz <tron_at_huapi.ba.ar >> <mailto:tron_at_huapi.ba.ar>> wrote: >> >> Pop tag means that the destination (network) is connected to a LSR, >> i.e., a router that this router knows that supports MPLS. >> This may be because he is receiving LDP from it indicating >> "implicit-null" as the tag for this prefix. >> >> Untagged means that the destination is known by some means (routing >> protocol?) but the next hop is not MPLS aware (this router is not >> receiving MPLS tag info for this prefix) so it will remove the stack >> before forwarding. >> >> In your example, the 11.1.68.0/24 <http://11.1.68.0/24> is locally >> connected, and the "next hop" is this router itself. >> The 11.1.6.6/32 <http://11.1.6.6/32> is connected to another router >> and there is no tag info >> for this prefix. May be the loopback is a /24 ? >> >> -Carlos >> >> >> Manouchehr Omari wrote: >> >> Pop tag means remove the top label and send the remaining payload. >> Untagged means the outgoing interface is not MPLS enabled remove >> the label >> and send the packet without label. >> >> I recommend you to read "MPLS Fundamentals" which cover these >> tips in >> detail. >> >> HTH >> >> >> On Sat, Dec 25, 2010 at 9:33 PM, Lefe Meedorf >> <feeldefreedom_at_gmail.com <mailto:feeldefreedom_at_gmail.com>>wrote: >> >> Hi, >> >> In my simple MPLS setup, I see following entires in "LFIB". >> >> R5#show mpls forwarding-table >> Local Outgoing Prefix Bytes tag Outgoing >> Next Hop >> tag tag or VC or Tunnel Id switched interface >> 16 Untagged 11.1.6.6/32 <http://11.1.6.6/32> 0 >> Se0/0 point2point >> 17 Pop tag 11.1.68.0/24 <http://11.1.68.0/24> 0 >> Se0/0 point2point >> >> What is the difference between "Untagged" and "Pop tag" ? >> 11.1.6.6 is R6 (i.e. PE) Loopback 0. >> 11.1.68.0/24 <http://11.1.68.0/24> is network between R6 and >> CE router. >> >> Topology >> ---(R5)----(R6)----(CE) >> >> R6 Lo : 11.1.6.6/32 <http://11.1.6.6/32> >> R6/CE : 11.1.68.0/24 <http://11.1.68.0/24> >> >> -- >> /Lefe Meedorf/ >> >> >> Blogs and organic groups at http://www.ccie.net >> >> >> _______________________________________________________________________ >> Subscription information may be found at: >> http://www.groupstudy.com/list/CCIELab.html >> >> >> >> Blogs and organic groups at http://www.ccie.net >> >> >> _______________________________________________________________________ >> Subscription information may be found at: >> http://www.groupstudy.com/list/CCIELab.html >> >> >> >> >> >> >> >> >> -- Carlos G Mendioroz <tron_at_huapi.ba.ar <mailto:tron_at_huapi.ba.ar>> >> LW7 EQI Argentina >> >> >> >> Blogs and organic groups at http://www.ccie.net >> >> _______________________________________________________________________ >> Subscription information may be found at: >> http://www.groupstudy.com/list/CCIELab.html >> >> >> >> >> >> >> >> > > -- > Carlos G Mendioroz <tron_at_huapi.ba.ar> LW7 EQI Argentina > > > Blogs and organic groups at http://www.ccie.net > > _______________________________________________________________________ > Subscription information may be found at: > http://www.groupstudy.com/list/CCIELab.html Blogs and organic groups at http://www.ccie.netReceived on Sun Dec 26 2010 - 21:07:48 ART
This archive was generated by hypermail 2.2.0 : Sat Jan 01 2011 - 09:37:49 ART