In this section:

Note

The following section is only applicable to the DSC Platform.

The scenarios described in this section, override the configuration of traffic transmitted on the AB Plane for a linkset (refer to Traffic Transmitted Only on the AB Plane for Linksets in a TTC Network). 

Feature Overview

The purpose of the feature is to provide traffic load sharing for network configurations where Telecommunication Technology Committee (TTC) AB Plane Loadshsaring is defined for a properly configured combined linkset in a routeset (with AB Plane Bit properly set for each linkset - one is A the other is B) or a routeset that is sending traffic over only one route.

Note

A properly configured combined linkset for this feature refers to

  • a combined linkset where one linkset is configured as A Plane, the other as B Plane or a single linkset carrying traffic in which case the AB Plane Bit setting is irrelevant
  • the routeset Load Sharing mode is set to TTC AB Plane

It is assumed that two or more links are provisioned in each linkset.

The following two linkset configuration scenarios are supported for properly configured combined TTC linksets:

  1. One linkset is transmitting traffic and the Routeset is configured in TTC AB Plane mode (referred to as the single linkset scenario; for related procedures, see To provision a single linkset scenario).
    1. the routeset uses two routes provisioned with different costs (for related procedure, see The routeset uses two routes provisioned with different costs)
      OR
    2. the routeset contains only one active/available linkset (for related procedure, see The routeset contains only one active/available linkset)
      OR

    3. combined linkset where less than half of the links are available in one linkset, but half or more of the links are available in the other linkset. For this scenario, the two linksets must be configured as one A Plane and one B Plane linksets (for related procedure, see Combined linkset where less than half of the links are available in one linkset, but half or more of the links are available in the other linkset)
      OR

    4. the routeset contains only one linkset (see The routeset contains only one linkset)

  2. In a TTC AB Plane Load Share mode Routeset, where less than half of the links in each linkset are available (referred to as Quasi-Normal/Quasi-Normal or combined linkset scenario; for related procedure, see To configure a combined linkset scenario for this feature).

In scenario 1, MSUs must be sent across one linkset for instances (a, b, c, and d). MSUs with Signaling Link Selection (SLS) values that have the same Link Selection Number (LSN) value must be sent through the same link.

In scenario 2, the AB Plane is respected as long as this configuration does not further unbalance traffic. Some MSUs might not be sent through their corresponding plane. For these MSUs, they must be send across the same link used to send the MSU with the same LSN value (but different AB Plane Bit).

 

Note

This feature complements the following two features:

  • Allow the user to select SLC (3-bit) and A/B plane
  • Traffic Transmitted Only on the AB Plane for Linksets in a TTC Network

For more information about these two features, refer to Configuring the A and B Plane Attribute in a TTC Network and Traffic Transmitted Only on the AB Plane for Linksets in a TTC Network, respectively. 

Single Linkset Scenario

According to TTC standard (JT Q.704 ), in the single linkset scenario, the LSN value should be used to select the outgoing link onto which an MSU will be sent. Therefore, two SLS values with the same LSN value must be sent through the same link .

Note

In NTT, the SLS is 5 bits and different parts of the SLS are considered relevant depending on the type of the outgoing linkset (STP to SEP, STP to STP, etc). Because the SLS in TTC is 4 bits, the NTT procedures cannot be applied directly. In particular, the 4 bit SLS in TTC is always considered to be a 3 bit LSN and a 1 bit A/B plane bit, regardless of the function of the outgoing linkset.

Combined Linkset Scenario

According to Nippon Telegraph and Telephone Corporation (NTT) documentation, in a combined linkset scenario where both linksets are in the Quasi-Normal state, typically the AB Plane Bit is respected and the MSUs are sent over the correct plane as long this action does not further unbalance traffic across all the available links. Two SLS values with the same LSN value must be sent through the same link in the case where the AB Plane Bit is not enforced.

Procedure to Configure the Single Linkset Scenario

Execute the instructions in the following procedure to configure one of the options for single linkset scenario for this feature.

To provision a single linkset scenario

  1. The routeset uses two routes provisioned with different costs.
    1. Log onto the Web UI.   
       
    2. Click MTP3.
       

    3. Create or select an MTP3 NA.

      Tip

      For detailed information about creating and configuring an NA, refer to Configuring an Network Appearance.


    4. Create a TTC NA.


    5. Create two linksets (the AB Plane Bit of each linkset can be set to any value, because this value is irrelevant for this scenario) and create at least two links in each linkset.

      For detailed information about creating and configuring Linksets, refer to Configuring Linksets.

    6. Do the following:

      1. Create a routeset that uses both linksets you just created.

      2. Set the LoadShare mode of the routeset to "TTC AB Plane".

      3. Change the route cost for one of the routes to a lower value than the the cost of the other route.  
        For information about creating and configuring routesets, refer to Configuring Routesets and Routes.
         
  2. The routeset contains only one active/available linkset.
     
    1. Log onto the Web UI.

    2. Create a TTC NA.

    3. Create two linksets and create at least two links in each linkset.
       
    4. Create one routeset that contains both linksets.

    5. Set the LoadShare mode of the routeset to "TTC AB Plane".

    6. Deactivate all the links in one of the linksets.

       
  3. Combined linkset where less than half of the links are available in one linkset, but half or more of the links are available in the other linkset. For this scenario, the two linksets must be configured as one A Plane and one B Plane linksets.

    1. Log onto the Web UI.

    2. Using the Web UI, create a TTC NA.

    3. Create two linksets (the AB Plane Bit must be set to A for one linkset and B for the other linkset).

    4. Create at least three links in each linkset (you can create more).
       
    5. Create a routeset that uses both linksets.

    6. Set the LoadShare mode of the routeset to "TTC AB Plane".

    7. Make more than half the links of one linkset go unavailable (this linkset will not carry any traffic in this scenario).

    8. Make half or less than half the links of the other linkset go unavailable (this linkset will carry all the traffic in this scenario).
       
  4. The routeset contains one linkset.

    1. Log onto the Web UI. 

    2. Click MTP3. 

    3. Create  a TTC NA. 

    4. Create a single linkset (the AB Plane Bit can be set to any value as it is irrelevant for this case).

    5. Create two or more links in the linkset.

    6. Create a routeset that uses the single linkset.

    7. Set the LoadShare Mode of the routeset to "TTC AB Plane"

Procedure to Configure the Combined Linkset Scenario

Execute the instructions in the following procedure for combined linkset scenario (can be referred to as Quasi-Normal/Quasi-Normal).

To configure a combined linkset scenario for this feature

  1. Log onto the Web UI.

  2. Using the Web UI create a TTC NA.

  3. Create two linksets (the AB Plane Bit must be set to A for one linkset and B for the other).

  4. Create at least three links in each linkset (you can create more).

  5. Create a routeset that uses both linksets.

  6. Set the LoadShare mode of the routeset to "TTC AB Plane".

  7. Make more than half the links in both linksets go unavailable (each linkset is in the Quasi-Normal state).

  • No labels