What is the maximum number of VPLS instances supported, and the maximum number of sites supported per VPLS instance, on MX Series routers?
The maximum number of VPLS instances supported on MX Series routers is 8,000.
This number is derived as follows:
The logical interface limit on an MX Series router is 64,000. In BGP VPLS, the default label block size is eight, which provides eight pseudowires per VPLS. Divide the number of logical interfaces by the number of pseudowires to get the maximum number of VPLS instances supported: 64,000/8 = 8,000.
In Junos OS 10.0 Release and later, use the label-block-size size statement to configure VPLS label block size as 2, 4, 8, or 16. If the block size is increased, the number of VPLS instances can be increased. With LDP VPLS, there is no concept of label block, so the number of logical interfaces used is based on the number of sites attached to the VPLS.
Theoretically, if there are fewer than eight sites per LDP VPLS, that network could scale to 8,000 logical interfaces and greater. However, the qualified tested maximum number is 8,000.
Currently, the flooding in VPLS is limited to 4,000 sites per VPLS mesh group. MX Series routers support 14 user-defined mesh groups. Therefore, the maximum number of sites possible is 56,000 (4000 x 14 = 56,000).
For more information, click Layer 2 VPNs and VPLS Feature Guide.