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Contributor
labrat
Posts: 29
Registered: ‎04-14-2009
0

p2mp questions

Hi all:

 

Reading JUNOS documents on subject of p2mp and have some questions regarding static p2mp configurations. Here is the diagram:

 

 

ce1---pe1---p3---p5---pe7

                      |         \

                      |          \

                     pe2     pe10

 

1) On pe1, i have three LSPs configured:

 

label-switched-path pe1->pe2 {
        to "pe2";
        p2mp p2mp->pe2;
}
label-switched-path pe1->pe7 {
        to "pe7";
        p2mp p2mp->pe7;
}
label-switched-path pe1->pe10 {
        to "pe10";
        p2mp p2mp->pe10;
}

 

are those configurations correct?

 

2) for branch nodes p3, p5, according to JUNOS documents, I should configure LSPs on those branch nodes too;

 

on p3:

 

label-switched-path p3->pe2 {
        to "pe2";
        p2mp p2mp->pe2;
}
label-switched-path p3->pe7 {
        to "pe7";
        p2mp p2mp->pe7;
}
label-switched-path p3->pe10 {
        to "pe10";
        p2mp p2mp->pe10;
}

 

on p5:

 

label-switched-path p5->pe7 {
        to "pe7";
        p2mp p2mp->pe7;
}
label-switched-path p5->pe10 {
        to "pe10";
        p2mp p2mp->pe10;
}

 

3) I captured some data from rsvp on pe1, after I created those p2mp LSP:

 

Jul 26 15:56:52.175328 RSVP send Path 10.100.3.1->10.100.3.2 Len=248 fe-0/0/0.10
Jul 26 15:56:52.175490   MessageID Len 12 Msg_ID: 34 Epoch: 7781352 (Ack Desired)
Jul 26 15:56:52.175555   Session13 Len 16 10.100.3.1(port/tunnel ID 6155 Ext-ID 10.100.3.1) Proto 0
Jul 26 15:56:52.175639   Hop      Len 12 10.100.0.1/0x08dd4490
Jul 26 15:56:52.175690   Time     Len  8 30000 ms
Jul 26 15:56:52.175755   SrcRoute Len 20  10.100.0.2 S 10.100.0.30 S
Jul 26 15:56:52.175807   LabelRequest Len  8 EtherType 0x800
Jul 26 15:56:52.175864   Properties Len 24 Primary path p2mp->r2 p2mp-pvc name
Jul 26 15:56:52.175920   SessionAttribute Len 16 Prio (7,0) flag 0x4 "r1->r2"
Jul 26 15:56:52.175979   Sender12 Len 20 P2MP Sender 10.100.3.1(port/lsp ID  1, branch ID 10)    SubGrpOrg ID 0xa640301
Jul 26 15:56:52.176033   SubLsp   Len  8 Destination 10.100.3.2
Jul 26 15:56:52.176116   Tspec    Len 36 rate 0bps size 0bps peak Infbps m 20 M 1500
Jul 26 15:56:52.176170   ADspec   Len 48 MTU 1500
Jul 26 15:56:52.176226   RecRoute Len 12  10.100.0.1

 

According to rfc4875, page 10:

 

"This section describes modifications made to the Path message format
as specified in [RFC3209] and [RFC3473]. The Path message is
enhanced to signal one or more S2L sub-LSPs. This is done by
including the S2L sub-LSP descriptor list in the Path message
as
shown below."

 

where is this S2L sub-LSP descriptor list"? this  "SubLsp   Len  8 Destination 10.100.3.2"? It is more like S2L_SUB_LSP IPv4 Object to me according to rfc4875, 19.3.

 

Also, what is this "Properties Len 24 Primary path p2mp->r2 p2mp-pvc name"? Is it a glue that tie the main LSP to those sub LSPs on those branch nodes together?

 

Thanks.

 

 

Contributor
wangqiang_3g@126.com
Posts: 37
Registered: ‎08-27-2011
0

回复: p2mp questions

hi,i having confuse with the p2mp :smileytongue:

Trusted Expert
Surya
Posts: 262
Registered: ‎08-25-2009
0

Re: p2mp questions

Hi,

 

If we have to bind PE2, PE7 and PE10 with P2MP LSP, then you need the below configs as highlighted in bold letters.

You don't need any LSP configs in branch nodes. Branch node would replicate the incoming labelled packets.

 

label-switched-path pe1->pe2 {
        to "pe2";
        p2mp p2mp-lsp;
}
label-switched-path pe1->pe7 {
        to "pe7";
        p2mp p2mp-lsp;
}
label-switched-path pe1->pe10 {
        to "pe10";
        p2mp p2mp-lsp;
}

 

 

As per the RFC-4875, S2L sub-LSP descriptor list is defined as below:

 

 

   <S2L sub-LSP descriptor list> ::= <S2L sub-LSP descriptor>
                                     [ <S2L sub-LSP descriptor list> ]

   <S2L sub-LSP descriptor> ::= <S2L_SUB_LSP>
                                [ <P2MP SECONDARY_EXPLICIT_ROUTE> ]

   Per the definition of <S2L sub-LSP descriptor>, each S2L_SUB_LSP
   object MAY be followed by a corresponding SERO.

 

hence as expected you see S2L_SUB_LSP IPv4 Object in the path message.

 

 

Properties object is vendor independent (Object-Type 204). Please refer below:

 

http://www.juniper.net/techpubs/en_US/junos10.0/information-products/topic-collections/nog-mpls-logs...

 

Regards

Surya

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