[j-nsp] Issue with pseudo-wire attempting to establish across non LSP path

Peter Kalogerakos pjkpub at gmail.com
Wed Sep 28 22:01:36 EDT 2011


David,

Each of the routers are running RSVP as the core MPLS protocol on the core facing interfaces in other words, we are not running LDP on the core. 


To clarify, these are VPLS connections. If you can visualize a ring type configuration where the top node BOXLABJ41 has a connection to BOXLABJ42 and BOXLABJ43.  BOXLABJ42 and BOXLABJ43 also have a connection to each other.   I also created a pair of named LSP's between 
	- BOXLABJ41 and BOXLABJ42 (LSP2)
	- BOXLABJ41 and BOXLABJ43 (LSP1
	- BOXLABJ42 and BOXLABJ43  (LSP_J42-43)\(LSP_J43-J42)

The issue exists when I remove the named LSP between BOXLABJ42 and BOXLABJ43. The vpls session, using vpls and pseudo-wire interchangeably, goes down when I disable the named LSP between J42 and J43. The VPLS session goes back up when I cost the IGP metrics to force IGP (ISIS) to prefer traffic across the links passing through BOXLABJ41 intermediate node. 

Below is a series of outputs demonstrating the working and failed conditions. 

admin at boxlabj41> show mpls lsp 
Ingress LSP: 2 sessions
To              From            State Rt P     ActivePath       LSPname
72.22.160.205   72.22.160.241   Up     0 *                      LSP2
72.22.160.240   72.22.160.241   Up     0 *                      LSP1
Total 2 displayed, Up 2, Down 0

Egress LSP: 2 sessions
To              From            State   Rt Style Labelin Labelout LSPname 
72.22.160.241   72.22.160.240   Up       0  1 FF       3        - LSP1
72.22.160.241   72.22.160.205   Up       0  1 FF       3        - LSP1
Total 2 displayed, Up 2, Down 0

***

admin at boxlabj42>show vpls connections instance ri_j42-j43 //output from router J43 Lo072.22.160.240
Instance: ri_j42-j43
  Local site: boxlabj42.10002 (1)
    connection-site           Type  St     Time last up          # Up trans
    2                         rmt   Up     Sep 26 19:22:10 2011           2
      Remote PE: 72.22.160.205, Negotiated control-word: No
      Incoming label: 262154, Outgoing label: 262145
      Local interface: lsi.1564161, Status: Up, Encapsulation: VPLS
        Description: Intf - vpls ri_j42-j43 local site 1 remote site 2

admin at boxlabj43> show vpls connections instance ri_j42-j43  //output from router J42 Lo072.22.160.205
Instance: ri_j42-j43
  Local site: boxlabj43.10002 (2)
    connection-site           Type  St     Time last up          # Up trans
    1                         rmt   Up     Sep 26 22:13:40 2011           2
      Remote PE: 72.22.160.240, Negotiated control-word: No
      Incoming label: 262145, Outgoing label: 262154
      Local interface: lsi.1138567, Status: Up, Encapsulation: VPLS
        Description: Intf - vpls ri_j42-j43 local site 2 remote site 1

*****

admin at boxlabj43> show mpls lsp         
Ingress LSP: 2 sessions
To              From            State Rt P     ActivePath       LSPname
72.22.160.240   72.22.160.205   Up     0 *                      LSP_J43-J42
72.22.160.241   72.22.160.205   Up     0 *                      LSP1  
Total 2 displayed, Up 2, Down 0

Egress LSP: 2 sessions
To              From            State   Rt Style Labelin Labelout LSPname 
72.22.160.205   72.22.160.240   Up       0  1 FF       3        - LSP_J42-43
72.22.160.205   72.22.160.241   Up       0  1 FF       3        - LSP2

admin at boxlabj42> show mpls lsp 
Ingress LSP: 2 sessions
To              From            State Rt P     ActivePath       LSPname
72.22.160.205   72.22.160.240   Up     0 *                      LSP_J42-43
72.22.160.241   72.22.160.240   Up     0 *                      LSP1
Total 2 displayed, Up 2, Down 0

Egress LSP: 2 sessions
To              From            State   Rt Style Labelin Labelout LSPname 
72.22.160.240   72.22.160.205   Up       0  1 FF       3        - LSP_J43-J42
72.22.160.240   72.22.160.241   Up       0  1 FF       3        - LSP1

****  

admin at boxlabj42>show route
*snip*
ri_j42-j43.l2vpn.0: 2 destinations, 2 routes (2 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

72.22.160.205:10002:2:1/96                
                   *[BGP/170] 2d 05:45:52, localpref 100, from 72.22.160.241
                      AS path: I
                    > to 72.22.160.13 via ge-0/0/9.0, label-switched-path LSP_J42-43
72.22.160.240:10002:1:1/96                
                   *[L2VPN/170/-101] 2w2d 01:50:03, metric2 1
                      Indirect


admin at boxlabj43>show route 
*snip*
ri_j42-j43.l2vpn.0: 2 destinations, 2 routes (2 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

72.22.160.205:10002:2:1/96                
                   *[L2VPN/170/-101] 2w2d 01:52:51, metric2 1
                      Indirect
72.22.160.240:10002:1:1/96                
                   *[BGP/170] 2d 05:49:23, localpref 100, from 72.22.160.241
                      AS path: I
                    > to 72.22.160.12 via ge-0/0/9.0, label-switched-path LSP_J43-J42
***
admin at boxlabj42> show configuration protocols mpls label-switched-path LSP_J42-43 | display set 
set protocols mpls label-switched-path LSP_J42-43 to 72.22.160.205

admin at boxlabj43> show configuration protocols mpls label-switched-path LSP_J43-J42 | display set 
set protocols mpls label-switched-path LSP_J43-J42 to 72.22.160.240


The following output demonstrates the non-working condition following the removal of the "label switched path LSP_J42-J43". The expectation is that the pseudo-wire will signal between the LERs BOXLABJ42 \ BOXLABJ43 across an established LSP, in this case LSP1 to LSP2 using BOXLABJ41 as the LSR rather that using non LSP direct-connect path. 

admin at boxlabj42> show vpls connections instance ri_j42-j43 
Instance: ri_j42-j43
  Local site: boxlabj42.10002 (1)
    connection-site           Type  St     Time last up          # Up trans
    2                         rmt   VC-Dn  Sep 26 19:22:10 2011           2
      Remote PE: 72.22.160.205, Negotiated control-word: No
      Incoming label: 262154, Outgoing label: 262145
      Local interface: lsi.1564161, Status: Up, Encapsulation: VPLS
        Description: Intf - vpls ri_j42-j43 local site 1 remote site 2


admin at boxlabj43> show vpls connections instance ri_j42-j43 

Instance: ri_j42-j43
  Local site: boxlabj43.10002 (2)
    connection-site           Type  St     Time last up          # Up trans
    1                         rmt   VC-Dn  Sep 26 22:13:40 2011           2
      Remote PE: 72.22.160.240, Negotiated control-word: No
      Incoming label: 262145, Outgoing label: 262154
      Local interface: lsi.1138567, Status: Up, Encapsulation: VPLS
        Description: Intf - vpls ri_j42-j43 local site 2 remote site 1
***
admin at boxlabj42> show mpls lsp 
Ingress LSP: 1 sessions
To              From            State Rt P     ActivePath       LSPname
72.22.160.241   72.22.160.240   Up     0 *                      LSP1
Total 1 displayed, Up 1, Down 0

Egress LSP: 1 sessions
To              From            State   Rt Style Labelin Labelout LSPname 
72.22.160.240   72.22.160.241   Up       0  1 FF       3        - LSP1
Total 1 displayed, Up 1, Down 0

Transit LSP: 0 sessions
Total 0 displayed, Up 0, Down 0


admin at boxlabj43> show mpls lsp 
Ingress LSP: 1 sessions
To              From            State Rt P     ActivePath       LSPname
72.22.160.241   72.22.160.205   Up     0 *                      LSP2
Total 1 displayed, Up 1, Down 0

Egress LSP: 1 sessions
To              From            State   Rt Style Labelin Labelout LSPname 
72.22.160.205   72.22.160.241   Up       0  1 FF       3        - LSP2
Total 1 displayed, Up 1, Down 0

Transit LSP: 2 sessions 
To              From            State   Rt Style Labelin Labelout LSPname 
72.22.160.240   72.22.160.241   Up       1  1 FF  299824        3 LSP1
72.22.160.241   72.22.160.240   Up       1  1 FF  299808        3 LSP1
Total 2 displayed, Up 2, Down 0

****
admin at boxlabj43> show route
*snip*
ri_j42-j43.l2vpn.0: 2 destinations, 2 routes (2 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

72.22.160.205:10002:2:1/96                
                   *[L2VPN/170/-101] 2w2d 02:29:29, metric2 1
                      Indirect
72.22.160.240:10002:1:1/96                
                   *[BGP/170] 2d 06:26:01, localpref 100, from 72.22.160.241
                      AS path: I
                    > to 72.22.160.12 via ge-0/0/9.0

admin at boxlabj43> show route 
*snip*

ri_j42-j43.l2vpn.0: 2 destinations, 2 routes (2 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

72.22.160.205:10002:2:1/96                
                   *[L2VPN/170/-101] 2w2d 02:29:29, metric2 1
                      Indirect
72.22.160.240:10002:1:1/96                
                   *[BGP/170] 2d 06:26:01, localpref 100, from 72.22.160.241
                      AS path: I
                    > to 72.22.160.12 via ge-0/0/9.0

**notice pw trying to establish across IGP \ non LSP path.**


Regards, 

Peter K.



On Sep 28, 2011, at 6:00 PM, David Ball wrote:

> On 28 September 2011 14:27, Peter K <pjkpub at gmail.com> wrote:
>> 
>> Goal is to deploy label switch routers specifically functioning only as PE
>> (distribution) nodes with direct connectivity to the P\PE (core) nodes and
>> avoid the configuration required for a full mesh of LSP’s and l2vpn
>> signaling between the P\PE core nodes and the PE distribution nodes.  Below
>> is an outline of requirements.
> 
>  Safe to assume you're running LDP on your LERs as well ?
> 
>> 
>> I am noticing the pseudo-wire is attempting to establish a session across a
>> routed link (with RSVP and MPLS enabled) without a defined LSP path causing
>> any pseudo-wires using that path to go down.   The pseudo-wire
>> re-establishes its connection when the IGP metric is modified and reroutes
>> traffic or when then named LSP is created between the two PE nodes.
>> Although this appears to be an issue regarding order of operations when
>> deploying a new node(d) in this configuration, is there a mechanism in place
>> to restrict pseudo-wires from trying to establish connections across a path
>> without an established LSP path across the connection?
> 
>  Not sure I follow here.  All your L2vpns traversing a given link
> from your LER to the LSR drop when a new one is being signalled?  When
> they drop, what is the output of a 'show l2vpn connections' for them ?
> 
> David



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