Hello,
Today I'm going to share with you, comparison of two methods of adding network elements to 1:1 multiplex section protection.
Problem Description
Adding points to the 1+1 linear multiplex section protection is easy to implement because it does not involve protocol transfer, judgment, and action. For the 1:N (1:1) linear multiplex section that requires protocol, what can be done more efficiently?
Environment setup: There are two OSN9560 and one OSN3500 on a newly-built network. For convenience, three network elements A, B, and C are used to describe: the original AC interconnection is configured as a 1:1 linear multiplex section protection. Add B network element between AC, the topology becomes ABC.
Process
It can be divided into two schemes: scheme 1: cut off the backup fiber first, scheme 2: cut off the main fiber first.
Option one (cut off the backup fiber first):
Configure the pass-through service and two 1:1 linear multiplex section protection groups (corresponding to the two directions of A and C) on the B network element in advance, and the two protection group protocols are in the active state;
A "locked" switch is issued on the A network element, and the C network element query is also in the locked state (the original connection relationship), and then the services uses the A-C main channel;
Disconnect the AC backup channel fiber and connect the backup channel fiber of the three network elements ABC, and the services is normal; //After the backup channel fiber is connected, the protection group status of the two directions of the B network element will become "locked", but due to services Still walking in the AC main channel, services is not affected.
Issue the "clear" command on network element A to check that the status of the four protection groups of network elements A, B, and C should be normal, and services will not be affected;
"Forced switching" is issued on the A network element. At this time, the service will use the ABC backup channel, and the service will be interrupted instantly. Check the status of the four protection groups of A, B, and C network elements, and they are all in the "Forced switching" state; A momentary interruption, the protocol is transmitted through the three-point loop, and the switching time is slightly longer than the single-stage linear protection switching time
Disconnect the A-C main optical fiber and connect them to the corresponding optical ports of the B network element, and the topology becomes A-B-C structure;
Send the "Clear" command to the A and C network elements to check that the protection group is in a normal state, and the service returns to the ABC main channel, and the service will be interrupted instantly;//Because the topology becomes two-stage linear protection, it must be separated from A and C If the "clear" command is issued, the services will be interrupted twice.
Perform the switching test in two sections, and modify the network data such as the optical fiber connection on the network management after no problem.
Option two (disconnect the main fiber first):
Configure the services that need to pass through in the B network element in advance;
A forced switching command is issued on the A network element to switch the A-C service to the backup channel, and the service is interrupted; //the first instant interruption
Cut off the A-C main channel fiber and connect the A-B-C main channel fiber;
Send the "clear" command to the A network element to query that the A-C status is normal, the service is restored on the A-B-C main channel, and the service is interrupted;//The second instant interruption
Disconnect the A-C backup channel optical fiber, connect the A-B-C backup channel, and the topology becomes A-B-C structure;
Add two linear protection groups (corresponding to the two directions of A and C) on the B network element, start the protocol, and check that the protocol status is normal. Since the service is on the main channel, the activation of the protocol will not affect the service;
Perform the switching test in two sections, and modify the network data such as the optical fiber connection on the network management after no problem.
Comparison of the two programs:
Solution 2 is simpler than Solution 1. This method is recommended because:
In the second scheme, only the pass-through service is configured for the B network element in advance, while the B network element in the scheme one is also pre-configured with linear protection groups in two directions.
It is for the above reasons that the protocol transfer and judgment between the three network elements and four protection groups in the first scheme requires attention to the protection group status, while the second scheme only needs to pay attention to the two protection group status of the A and C network elements;
During the operation of Scheme 2 (that is, except for the switching test), the service interruption time is one less than the number of interruptions in Scheme 1, and the switching time of the first instant interruption is shorter. Of course, this depends on the user equipment’s impact on the interruption time. Sensitivity.
Conclusions
The meaning of "lock" in the 1:N protocol: lock the backup channel, each working channel does not act, that is, it will not switch to the backup channel;
The 1:N linear multiplex section protocol parameters do not have the node parameters similar to the ring multiplex section protocol. The protocol only talks about the status and does not judge the network element nodes. Therefore, as long as the optical port is connected, the status will be transmitted, judged, and acted. Therefore, Solution one should pay attention to the state of the two-stage linear protection group.
The priority of command switching in the protocol: from high to low, it is clear-forced switching-manual switching-practice switching.
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