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how bypass LSP of link-protection is created ?

  • 1.  how bypass LSP of link-protection is created ?

    Posted 05-22-2017 21:02

    Hi,

    I think that LSP bypass of link-protection should follow the IGP if the link down. But in my case, it doesn't.

    My configuration is very simple. I just set link-protection in all interfaces (on all routers).

    But when i check the bypass LSP for protecting interface ge-0/0/0 on R1, it does not follow the IGP path: R1->R2->R3->R4, it follow the futher path through: R1->R5->R6->R2->R3->R4. I checked some others bypass LSP, almost of them still don't follow the IGP path. 

     

    Thanks for any explanations.

     

     

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  • 2.  RE: how bypass LSP of link-protection is created ?

    Posted 05-22-2017 22:27

    Hi,

     

    As per our documentation, it says following:

     

    "When link protection is configured for an interface and an LSP that traverses this interface, a bypass LSP is created that will handle this traffic if the interface fails. The bypass LSP uses a different interface and path to reach the same destination. The path used can be configured explicitly, or you can rely on CSPF. The RSVP metric for the bypass LSP is set in the range of 20,000 through 29,999 (this value is not user configurable)."

     

    In your case, is it always the case that Bypass LSP is computed using the longer path? What happens if you clear the Bypass LSP and check?

     

    Thanks

     



  • 3.  RE: how bypass LSP of link-protection is created ?

    Posted 05-23-2017 19:11

    Hi 



  • 4.  RE: how bypass LSP of link-protection is created ?

     
    Posted 05-26-2017 23:42

    Hi Folks,

    LSPs must be tagged for node-link protection to make use of the bypass LSPs, and you can provide an ERO list to influence the CSPF-based routing of the bypass LSP.

     

     

    https://www.juniper.net/documentation/en_US/junos/topics/reference/configuration-statement/bypass-edit-protocols-rsvp.html

     

    Syntax

    bypass bypass-name {

    bandwidth bps;

    description text;

    hop-limit number;

    no-cspf;

    path address <strict | loose>;

    priority setup-priority reservation-priority;

    to address;

    }

     

    Description

    Enables you to configure specific bandwidth and path constraints for a bypass LSP. It is possible to individually configure multiple bypass LSPs. If you do not configure the bypass LSPs individually, they all share the same path and bandwidth constraints.

     

    If you specify the bandwidth, hop-limit, and path statements for the bypass LSP, these values take precedence over the values configured at the [edit protocols rsvp interface interface-name link-protection] hierarchy level. The other attributes (subscription, no-node-protection, and optimize-timer) are inherited from the general constraints.

     

    Options

    bypass-name—(Required) Specify a name for the bypass LSP. The name can be up to 64 characters.

     

    description—Provides a textual description of the bypass LSP. Enclose any descriptive text that includes spaces in quotation marks (" "). Any descriptive text you include is displayed in the output of the show mpls lsp bypass detail command and has no effect on the operation of the bypass LSP. The description text can be no more than 80 characters in length.

     

    to address—(Required) Specify the address for the interface of the immediate next-hop node (for link protection) or the next-next-hop node (for node-link protection). The address specified determines whether this is a link protection bypass or a node-link protection bypass. On multiaccess networks (for example, a LAN), this address is also used to specify which next-hop node is being protected.

     

    The remaining statements are explained separately.

     

    Required Privilege Level

    routing—To view this statement in the configuration.

     

    routing-control—To add this statement to the configuration.

     

    -rengar



  • 5.  RE: how bypass LSP of link-protection is created ?

     
    Posted 05-26-2017 23:43
      |   view attached


  • 6.  RE: how bypass LSP of link-protection is created ?

    Posted 05-28-2017 21:33

    Hi , thanks for ur information,

    That way is too manual to create the bypass LSPs. They should be relied on CSPF. As i said before, in some case, the bypass LSPs donnt follow the shorted path to protect the interface when it goes down.

    My colleagues are in the same situation with me and we dont understand why.

     

    Thanks again.



  • 7.  RE: how bypass LSP of link-protection is created ?

    Posted 05-30-2017 02:17

    Hi,

     

    Can you please check the ted database at each hop and see the metric to reach the nexthop? It might be possible that according to CSPF computation, longer path is only meeting the criteria even though we think metric wise it should use the shorter path.

     

    Also enabling the traceoptions under [edit protocols mpls] with cspf flag and [edit protocols rsvp] would give some more clue.

     

    Hope this helps.

     

    Thanks



  • 8.  RE: how bypass LSP of link-protection is created ?

    Posted 05-30-2017 19:41

    Hi,

    I met these problems in the real network. Now it work stablely, I will take a lab to make sure that whether it work right or not. So i will give you my result when i get it.

    Thanks for your answer !



  • 9.  RE: how bypass LSP of link-protection is created ?

    Posted 08-22-2017 21:23

    Hi.

     

    Bypass can be created with no-cspf command in protocols mpls ?



  • 10.  RE: how bypass LSP of link-protection is created ?

    Posted 08-27-2017 19:56

    Hi,

     

    I guess not. Once you configure no-cspf, LSP will be signalled without using TED database. you can refer to below links for more understanding on no-cspf.

     

    https://www.juniper.net/documentation/en_US/junos/topics/reference/configuration-statement/no-cspf-edit-protocols-mpls.html

     

    https://forums.juniper.net/t5/Routing/no-cspf/td-p/206279

     

    root@P1_re# show protocols mpls
    admin-groups {
        Left 1;
        Right 2;
        Gold 3;
        Silver 4;
        bronze 5;
    }
    no-cspf;
    label-switched-path to-P2 {
        to 172.16.0.2;
        admin-group exclude Gold;
        link-protection;
    }
    interface ge-0/0/2.0;
    interface ge-0/0/3.0 {
        admin-group Gold;
    }
    interface ge-0/0/4.0 {
        admin-group Gold;
    }
    interface ge-0/0/5.0 {
        admin-group Gold;

    [edit]
    root@P1_re# show protocols rsvp
    interface ge-0/0/5.0;
    interface ge-0/0/4.0;
    interface ge-0/0/3.0;
    interface ge-0/0/2.0 {
        link-protection;
    }
    interface ge-0/0/1.0;

    [edit]
    root@P1_re# run show mpls lsp extensive
    Ingress LSP: 1 sessions

    172.16.0.2
      From: 172.16.0.1, State: Up, ActiveRoute: 0, LSPname: to-P2
      ActivePath:  (primary)
      Link protection desired
      LSPtype: Static Configured, Penultimate hop popping
      LoadBalance: Random
      Encoding type: Packet, Switching type: Packet, GPID: IPv4
     *Primary                    State: Up
        Priorities: 7 0
        SmartOptimizeTimer: 180
              Exclude: Gold
        Received RRO (ProtectionFlag 1=Available 2=InUse 4=B/W 8=Node 10=SoftPreempt 20=Node-ID):
              172.16.0.2(flag=0x20) 10.0.0.7(Label=3)
        7 Aug 27 19:41:26.461 Self-ping ended successfully
        6 Aug 27 19:41:25.719 Selected as active path
        5 Aug 27 19:41:25.718 Record Route:  172.16.0.2(flag=0x20) 10.0.0.7(Label=3)
        4 Aug 27 19:41:25.718 Up
        3 Aug 27 19:41:25.718 Self-ping started
        2 Aug 27 19:41:25.718 Self-ping enqueued
        1 Aug 27 19:41:25.692 Originate Call
      Created: Sun Aug 27 19:41:25 2017
    Total 1 displayed, Up 1, Down 0

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

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

    [edit]
    root@P1_re# run show rsvp session
    Ingress RSVP: 1 sessions
    To              From            State   Rt Style Labelin Labelout LSPname
    172.16.0.2      172.16.0.1      Up       0  1 SE       -        3 to-P2
    Total 1 displayed, Up 1, Down 0

    Egress RSVP: 0 sessions
    Total 0 displayed, Up 0, Down 0

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

    [edit]
    root@P1_re#

     

     

    HTH Smiley Happy