Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 
New Member

PNNI nodes and interfaces


i'm wondering how can i make a certain physical interface of an ATM switch

member of a particular node.

it's like let's say i have node 1 at level 88 and node 2 at level 72 ... and i want to make one interface member of node 2.

i know about the rule .... of missing level 80 ... in the above ex .....

thank you,

mihai iancu


Re: PNNI nodes and interfaces

You can make a particular interface member of a particular node.Border nodes are nodes that participate in a PNNI peer group and maintain connections to other peer groups. A border node is a member of only one peer group. Connections to other nodes within a peer group are called inside connections, and connections to nodes in other peer groups are called outside connections. A border node is any node that is configured for both inside and outside connections. Please go through the follwoing document fo more information:

New Member

Re: PNNI nodes and interfaces


thank you for your answer.

let's try to go a little bit further:

dslam01#sh atm pnni interf

PNNI Interface(s) for local-node 1 (level=88):

Local Port Type RCC Hello St Deriv Agg Remote Port Rem Node(No./Name)

~~~~~~~~~~~~~ ~~~~~ ~~~ ~~~~~~~~ ~~~~~~~~~~ ~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~

ATM0/1 Phy UP comm_out 0 1000000B 17

ATM0/2 Phy UP 2way_in n/a ATM0/1 9 dslam01.subten

PNNI Interface(s) for local-node 2 (level=80):

Local Port Type RCC HrzLn St Deriv Agg Remote Port Rem Node(No./Name)

~~~~~~~~~~~~~ ~~~~~ ~~~ ~~~~~~~~ ~~~~~~~~~~ ~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~

222E000 HrzLn UP 2way 0 30000022 17

as you can see we have node 1 the lowest level and you can see all atm interfaces belonging to this node ... this is way the atm0/1 is common outside because it speaks with a neighbor which has a higher level.

now - we do have a second node - no 2 - but i don't know how to make atm0/1 member of node 2 - this way i will have 2way inside.

now - i heard something about the PNNI specs .. saying that by default all interfaces in an atm switch belong to the node with the lowest level ... but i didn't find anything yet.... do you know if this is true?

thank you,


New Member

Re: PNNI nodes and interfaces

What is you pnni topology??

It looks like you are doing MPG/HPNNI. On ATMF PNNI Spec., you should only assosicate one node per interface. In addition, you should only have one "real" node per switch for the single ATM domain configuration.

In your example, I believe you have one "real" node - level 88 and few parent nodes - level 80 and 72 (may be more). In "normal" HPNNI/MPG setup, the higher level nodes are LGN. They will not active until the switch become PGL. All the outside link will become comman outside link when they have comman parent (LGN).

Actually, the "2 way inside" link is there, if there is "comman outside". It is the SVCC RCC between PGL (as the display on your node 2).

It is hard to explan and image what is happening right there. The best way is to download the PNNI spec from ATM Fourm (af-pnni-0055.00), and read the section 3. I believe CCO has something similar. However, I can only found this:

New Member

Re: PNNI nodes and interfaces


you are right and you hit the point that generated all this ... to activate node 2 you have to make node 1 PGL ... which means i will have to alter the relationship inside a peer group just because i want to activate a logical node.

why do i have to make node 1 PGL in order to activate node 2 which ... btw ... will be parent for child 1 ...

yes you are right - there is a link - logical - horizontal link - between the real physical node at level 72 and the logical node at level 72.

is it because i can have only one "real" node ... and by default .. according to specs ... all interfaces belong to the node with the lowest level?

thank you again for your answer ... and yes ... i'm reading again that pdf .... it seems nothing can beat RFCs and forum specs ...

New Member

Re: PNNI nodes and interfaces

For your first question, why you have to change you relationship inside your peer group?? The reason for PGL/LGN is create a way to automatically "adjust" and "change" the network in case you have network failure. PGL/LGN suppose to discover all the ways to connect each other without user interaction.

Yes, you can have multiple active "real" nodes within a same switch (btw, cisco atm switch is really weak on this area.) However, you really have to look after the atm routing between them. The routing entres may not leak between atm node correctly. Static routing/route summary may be required in this case. The only reason you really need this is when you have atm switch do not support extened DTL (I have a lot of those in my network).

Well, I read you question again,. I believe you may have a "lop-sided" hierarchical network. It means you have "real" node on every level, and skipped some levels on some peer groups (level 88 to level 72 directly.) BTW, you don't need to have all the node/level on the switch. level 88 and 72 is allow. However, if you have level 80 somewhere in you network , this box will never be PGL for the network.

Anyway, if you want to do SPG, you have to define all the node (72 and 88) and two seperate "real" node and they have no parent/child relation. You have to configurate the routing between them.

I don't have example on cisco. I am using someone ease box to do it. BTW, it is on the af-pnni-0055.00 Appendix I.

CreatePlease to create content