[dualtor]Add a new dual tor topo dualtor-56

[bingwang-ms]

Signed-off-by: bingwang bingwang@microsoft.com

Description of PR

Summary:
Fixes # (issue)
This commit is to add a new dual tor topology dualtor-56.

Type of change

• Bug fix
• Testbed and Framework(new/improvement)
• Test case(new/improvement)

Approach

What is the motivation for this PR?

This PR is to add a new dual tor topology dualtor-56, which is based on t0-56 topo and implemented in dual tor structure.

How did you do it?

How did you verify/test it?

Verified by deploying a new dualtor-56 testbed and run test_link_flap and test_lag_2. All testcases passed.
The bgp status was also verified.

# show ip bgp sum

IPv4 Unicast Summary:
BGP router identifier 10.1.0.32, local AS number 65100 vrf-id 0
BGP table version 43693
RIB entries 12809, using 2356856 bytes of memory
Peers 4, using 83680 KiB of memory
Peer groups 4, using 256 bytes of memory


Neighbhor      V     AS    MsgRcvd    MsgSent    TblVer    InQ    OutQ  Up/Down      State/PfxRcd  NeighborName
-----------  ---  -----  ---------  ---------  --------  -----  ------  ---------  --------------  --------------
10.0.0.57      4  64600      19711      30104         0      0       0  01:00:14             6401  ARISTA01T1
10.0.0.59      4  64600      30046      37796         0      0       0  00:11:15             6401  ARISTA02T1
10.0.0.61      4  64600      19826      36462         0      0       0  01:07:36             6401  ARISTA03T1
10.0.0.63      4  64600      26197      39356         0      0       0  00:04:34             6401  ARISTA04T1

Total number of neighbors 4

Any platform specific information?

No.

Supported testbed topology if it's a new test case?

No.

Documentation

No.