Discussion in 'Cisco' started by Ank, Jul 3, 2007.

  1. Ank

    Ank Guest

    Dear All,

    Could anyone please tell me the basic and pratical difference between
    MSP and SNCP?
    Also can someone tell me when can we use MSP and when can we go for

    I know the practical set-up for both but couldn't figure out when to
    use which one of these two. With advantages and disadvantages of

    Hope the reader would be clear with my query and will be able to
    provide me the details.

    Thanks for your inputs in advance.

    Ank, Jul 3, 2007
    1. Advertisements

  2. Ank


    Jun 12, 2009
    Likes Received:
    MSP-SNCP slightly described

    MSP(Multiplex Section Protection) is a per span protection.

    A service line is protected using another line, called a protection line. If an error occurs, the protection mechanism should switch over to the protection line. There are two main protection schemes for the multiplex section:
    • 1+1 : Traffic is simultaneously transmitted over working and protecting lines (or cards if it is for hiT i.e. MSP bridge). The incoming traffic is select from the line that delivers signal in best condition (specifically switch fabric selector is responsible for making the selection in a HiT).
    o Switching type: unidirectional or bi-directional
    o Operation type: revertive or non-revertive

    • 1:N : A 1:N multiplex section protection system consists of N traffic-carrying multiplex sections that are to be protected by an additional multiplex section. In this scheme only one of the working sections can be protect at a time. The additional multiplex section can be used to carry low-priority traffic (unprotected) when it is not used as a protection section for the rest N working sections.
    o 1:N with N<=14 for STM-1/4/16 and N<=7 for STM-16/64
    o Switching type: bi-directional
    o Operation type: revertive

    • 1:1 : This is a special case of 1:N protection scheme. In case of a failure on the working path, traffic is switched to protecting path.
    o Switching type: bi-directional
    o Operation type: revertive

    SubNetwork Connection Protection. is a per path protection.

    SNCP is a network protection mechanism for SDH networks providing path protection (end-to-end protection). The data signal is transmitted in a ring structure via two different paths and can be implemented in line or ring structures. The changeover criteria are specified individually when configuring a network element. A protection protocol is not required. The switchover to protection path occurs in the non-revertive mode, i.e. if traffic was switched to the protection path due to a transmission fault, there is no automatic switch-back to the original path once the fault is rectified, but only if there is a fault on the new path (the one labeled as “protecting” and currently services traffic).

    SNCP is a 1+1 protection scheme (one working and one protection transport entity). Input traffic is broadcasted in two routes (one being the normal working route and the second one being the protection route).

    Assume a failure free state for a path from a node B to a node A. Node B bridges the signal destined to A from other nodes on the ring, both on working and protecting routes. At node A, signals from these two routes are continuously monitored for path layer defects and the better quality signal is selected.
    Now consider a failure state where fiber between node A and node B is cut. The selector switches traffic on the standby route when the active route between node A and node B is failed.

    In order to prevent any unnecessary or spurious protection switching in the presence of bit errors on both paths, a switch will typically occur when the quality of the alternate path exceeds that of the current working path by some threshold (e.g., an order of magnitude better BER). Consecutively, any case of failure drops in SNCP’s decision mechanism.
    Last edited: Jun 12, 2009
    mikep_7, Jun 12, 2009
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.