Question about SONET

acidsatyracidsatyr Member Posts: 111
in CCIE
Hi all,

Since I've never seen a working SONET configuration, routers with PoS interfaces, etc, i was wondering, how are routers connected to the SONET ring.
Say, 5 routers at different locations are connected with their PoS interfaces to ADMs and then directly to SONET ring. So how do they appear to each other? As i understand even on this ring topology, routers appear as they are on point to point interfaces. But how does that work? Do the interfaces belong to same shared subnet or is it different subnet for each connection.
Thx for hlp
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Comments

  • kryollakryolla Member Posts: 785
    sonet is layer 1 and we use ppp and hdlc as our layer 2 for our OC3 links. for ppp both ends can be on seperate subnets thus the peer neighbor route. The only difference with POS interfaces are the redundancy config for working and protect used for sonet
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  • acidsatyracidsatyr Member Posts: 111
    kryolla wrote: »
    sonet is layer 1 and we use ppp and hdlc as our layer 2 for our OC3 links. for ppp both ends can be on seperate subnets thus the peer neighbor route. The only difference with POS interfaces are the redundancy config for working and protect used for sonet

    So for 5 routers connected to sonet ring i would need 10 subnets for full mesh? The pos interface gets divided to subinterfaces?
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  • networker050184networker050184 Mod Posts: 11,962 Mod
    acidsatyr wrote: »
    So for 5 routers connected to sonet ring i would need 10 subnets for full mesh? The pos interface gets divided to subinterfaces?


    There are several ways to do it. For a point to point circuit we will go with PPP like kryolla pointed out straight to the router. If we want a ring we will drop the SONET onto an ONS/Nortel device and do ethernet handoff to the routers. You then use your dot1q subinterfaces. Its just a transport technology and you can run different L2 encapsulations over it.
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  • kryollakryolla Member Posts: 785
    acidsatyr wrote: »
    So for 5 routers connected to sonet ring i would need 10 subnets for full mesh? The pos interface gets divided to subinterfaces?

    POS is point to point just like serial interface you might be able to run FR idk, if you want multi-access then you would do what networker suggested and have an ethernet drop off
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