Hi Bryan,
yeah.. still wondering what's going on here.
Someone suggested to me that targeted ldp is used more for mpls
applications such as atom, not so much for plain label switching
between directly connected routers. But, t-ldp is also mentioned as a
way of making ldp sessions more resilient in case the directly
connected interface between two ldp peers breaks.
The way I understand it, there are two ways of configuring a protected
ldp session.
1. 'mpls ldp neighbor <ip> targeted ldp' in global config mode
2. 'mpls ip' under the interface + 'mpls ldp session protection' in
global config mode
So really with ldp session protection, you have both a directly
connected ldp session and a 'targeted' ldp session active at the same
time.
When I try option 1 and remove the 'mpls ip' command from the
interface, the labels disappear from the lfib, but the targeted ldp
sesions is up. If leave the 'mpls ip' command on the interface, I do
receive the labels.
So my questions are :
1. Why are there different commands to configure a protected ldp
session, that seem to do the same thing?
2. When should I configure a targeted ldp session and what is it used
for?
3. Why am I not receiving labels across a targeted ldp session between
directly connected neighbors?
PE4#sh mpls ldp neighbor
Peer LDP Ident: 1.1.1.1:0; Local LDP Ident 4.4.4.4:0
TCP connection: 1.1.1.1.646 - 4.4.4.4.13537
State: Oper; Msgs sent/rcvd: 15/15; Downstream
Up time: 00:00:15
LDP discovery sources:
FastEthernet1/0, Src IP addr: 172.16.14.1
Addresses bound to peer LDP Ident:
1.1.1.1 172.16.12.1 172.16.14.1
Peer LDP Ident: 3.3.3.3:0; Local LDP Ident 4.4.4.4:0
TCP connection: 3.3.3.3.646 - 4.4.4.4.14581
State: Oper; Msgs sent/rcvd: 15/15; Downstream
Up time: 00:00:13
LDP discovery sources:
FastEthernet3/0, Src IP addr: 172.16.34.3
Addresses bound to peer LDP Ident:
3.3.3.3 172.16.13.3 172.16.23.3 172.16.34.3
PE4#sh mpls forwarding-table 192.168.2.0
Local Outgoing Prefix Bytes Label Outgoing Next Hop
Label Label or VC or Tunnel Id Switched interface
23 25 192.168.2.0/24 0 Fa1/0
172.16.14.1
19 192.168.2.0/24 0 Fa3/0
172.16.34.3
PE4#
PE4#sh run int fastEthernet 1/0
Building configuration...
Current configuration : 105 bytes
!
interface FastEthernet1/0
ip address 172.16.14.4 255.255.255.0
duplex auto
speed auto
mpls ip
end
PE4#sh run int fastEthernet 3/0
Building configuration...
Current configuration : 105 bytes
!
interface FastEthernet3/0
ip address 172.16.34.4 255.255.255.0
duplex auto
speed auto
mpls ip
end
PE4#
PE4#conf t
Enter configuration commands, one per line. End with CNTL/Z.
PE4(config)#int fastEthernet 3/0
PE4(config-if)#no mpls ip
PE4(config)#int fastEthernet 1/0
PE4(config-if)#no mpls ip
PE4(config-if)#exit
PE4(config)#mpls ldp neighbor 1.1.1.1 targeted ldp
PE4(config)#mpls ldp neighbor 3.3.3.3 targeted ldp
PE4(config)#
PE4#sh mpls ldp neighbor
*Oct 11 17:37:53.215: %SYS-5-CONFIG_I: Configured from console by
console
Peer LDP Ident: 3.3.3.3:0; Local LDP Ident 4.4.4.4:0
TCP connection: 3.3.3.3.646 - 4.4.4.4.28418
State: Oper; Msgs sent/rcvd: 268/268; Downstream
Up time: 03:41:25
LDP discovery sources:
Targeted Hello 4.4.4.4 -> 3.3.3.3, active, passive
Addresses bound to peer LDP Ident:
3.3.3.3 172.16.13.3 172.16.23.3 172.16.34.3
Peer LDP Ident: 1.1.1.1:0; Local LDP Ident 4.4.4.4:0
TCP connection: 1.1.1.1.646 - 4.4.4.4.24502
State: Oper; Msgs sent/rcvd: 35/36; Downstream
Up time: 00:18:32
LDP discovery sources:
Targeted Hello 4.4.4.4 -> 1.1.1.1, active, passive
Addresses bound to peer LDP Ident:
1.1.1.1 172.16.12.1 172.16.14.1
PE4#
PE4#sh mpls forwarding-table 192.168.2.0
Local Outgoing Prefix Bytes Label Outgoing Next Hop
Label Label or VC or Tunnel Id Switched interface
23 No Label 192.168.2.0/24 0 Fa1/0
172.16.14.1
No Label 192.168.2.0/24 0 Fa3/0
172.16.34.3
PE4#
PE4#sh mpls forwarding-table
Local Outgoing Prefix Bytes Label Outgoing Next Hop
Label Label or VC or Tunnel Id Switched interface
16 No Label 3.3.3.3/32 41402 Fa3/0
172.16.34.3
17 No Label 2.2.2.2/32 0 Fa1/0
172.16.14.1
No Label 2.2.2.2/32 0 Fa3/0
172.16.34.3
18 No Label 1.1.1.1/32 0 Fa1/0
172.16.14.1
19 No Label 172.16.24.0/24 0 Fa1/0
172.16.14.1
No Label 172.16.24.0/24 0 Fa3/0
172.16.34.3
20 No Label 172.16.13.0/24 0 Fa3/0
172.16.34.3
21 No Label 172.16.12.0/24 0 Fa1/0
172.16.14.1
22 No Label 172.16.23.0/24 0 Fa3/0
172.16.34.3
23 No Label 192.168.2.0/24 0 Fa1/0
172.16.14.1
No Label 192.168.2.0/24 0 Fa3/0
172.16.34.3
24 No Label 12.12.12.2/32 0 Fa1/0
172.16.14.1
No Label 12.12.12.2/32 0 Fa3/0
172.16.34.3
PE4#
Attached a topology diagram. The link between PE1 and PE2 was shut
during the lab :
PE4#sh ip int brief
Interface IP-Address OK? Method
Status Protocol
FastEthernet0/0 unassigned YES NVRAM administratively
down down
FastEthernet1/0 172.16.14.4 YES NVRAM
up up
FastEthernet1/1 unassigned YES NVRAM administratively
down down
FastEthernet2/0 172.16.24.4 YES NVRAM administratively
down down
FastEthernet2/1 unassigned YES NVRAM administratively
down down
FastEthernet3/0 172.16.34.4 YES NVRAM
up up
FastEthernet3/1 unassigned YES NVRAM administratively
down down
FastEthernet4/0 unassigned YES NVRAM
up up
FastEthernet4/1 unassigned YES NVRAM administratively
down down
SSLVPN-VIF0 unassigned NO unset
up up
Loopback0 4.4.4.4 YES NVRAM
up up
PE4#
[GroupStudy removed an attachment of type image/jpg which had a name of MPLS Lab.jpg]
On 11/10/2009, at 10:18 , Bryan Bartik wrote:
> Marcel,
>
> Are you still having this issue? Can you post configs and topology?
>
> On Wed, Oct 7, 2009 at 6:13 PM, Marcel Lammerse <m.lammerse_at_mac.com>
> wrote:
>
>> Experts,
>>
>> here I have a load-balanced path between directly connected ldp
>> speakers :
>>
>> PE4#sh mpls forwarding-table 192.168.2.0
>> Local Outgoing Prefix Bytes Label Outgoing
>> Next Hop
>> Label Label or VC or Tunnel Id Switched interface
>> 22 25 192.168.2.0/24 0 Fa1/0
>> 172.16.14.1
>> 23 192.168.2.0/24 0 Fa3/0
>> 172.16.34.3
>> PE4#
>>
>> PE4#sh mpls ldp bindings 192.168.2.0 24 detail
>> lib entry: 192.168.2.0/24, rev 22, chkpt: none
>> local binding: label: 22 (owner LDP)
>> Advertised to:
>> 1.1.1.1:0 3.3.3.3:0
>> remote binding: lsr: 1.1.1.1:0, label: 25
>> remote binding: lsr: 3.3.3.3:0, label: 23
>> route information: state: none, table: default,
>> next-hop: 172.16.14.1, remote label: 25
>> route information: state: none, table: default,
>> next-hop: 172.16.34.3, remote label: 23
>>
>> If I change the ldp sessions to t-ldp, and keep everything else the
>> same,
>> the labels seem to disappear and traffic appears to go out untagged :
>>
>> PE4#sh mpls forwarding-table 192.168.2.0
>> Local Outgoing Prefix Bytes Label Outgoing
>> Next Hop
>> Label Label or VC or Tunnel Id Switched interface
>> 22 No Label 192.168.2.0/24 0 Fa1/0
>> 172.16.14.1
>> No Label 192.168.2.0/24 0 Fa3/0
>> 172.16.34.3
>> PE4#
>>
>> PE4#sh mpls ldp bindings 192.168.2.0 24 detail
>> lib entry: 192.168.2.0/24, rev 22, chkpt: none
>> local binding: label: 22 (owner LDP)
>> Advertised to:
>> 3.3.3.3:0 1.1.1.1:0
>> remote binding: lsr: 3.3.3.3:0, label: 23
>> remote binding: lsr: 1.1.1.1:0, label: 25
>> route information: state: none, table: default,
>> next-hop: 172.16.14.1, remote label: <----- no label
>> route information: state: none, table: default,
>> next-hop: 172.16.34.3, remote label: <----- no label
>> PE4#
>>
>> I'm a bit confused by this. I would have expected the traffic to
>> continue
>> to be labeled and the labels to remain the same.
>>
>> Can anyone shed some light on why this happens?
>>
>> Thanks,
>> Marcel
>>
>>
>> Blogs and organic groups at http://www.ccie.net
>>
>> _______________________________________________________________________
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>> http://www.groupstudy.com/list/CCIELab.html
>>
>>
>>
>>
>>
>>
>>
>>
>
>
> --
> Bryan Bartik
> CCIE #23707 (R&S), CCNP
> Sr. Support Engineer - IPexpert, Inc.
> URL: http://www.IPexpert.com
>
>
> 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
Received on Sun Oct 11 2009 - 18:47:58 ART
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