MPLS for SONiC infrastructure HLD

[qbdwlr]

PR	state
opencomputeproject/SAI#1181	merged
sonic-net/sonic-sairedis#815	merged with sonic-net/sonic-sairedis#816
sonic-net/sonic-sairedis#824 (vslib)	merged
sonic-net/sonic-swss-common#469	merged
sonic-net/sonic-buildimage#7195 (libnl3)	merged
sonic-net/sonic-swss#1686 (cfgmgr/orchagent/tests)	merged
sonic-net/sonic-utilities#1537	merged
sonic-net/sonic-swss#1871 (fpmsyncd)	merged
sonic-net/sonic-buildimage#7881 (sonic-yang-models)	merged
sonic-net/sonic-mgmt#3483	under-review

[ghost]

All CLA requirements met.

[TACappleman]

Hi, My team is also about to start working on coding up MPLS support in SONiC following a similar design to this one. Please could you get in touch with me on [email protected] so we can coordinate our work?

Regarding this design, there are a couple of additional features we are planning to add. Are these ones you've considered?

• Popping a label then basing the forwarding decision on the next header (either a following label or IP header). Related to this, popping a label that is associated with a given VRF, then routing within that VRF based on the following IP header.
• Support for specifying uniform or pipe TTL mode.

[lguohan]

as comments

[rlhui]

Could we please add in the doc current limitation for using FRR?

[rlhui]

Please add description for PHP

[rlhui]

Please add description if there's dependency that the interface should already have IPv4/IPv6 address configured. Is this dependency supported if Yang model is used for the configuration?

[zhangyanzhao]

Can anyone help to approve and merge this HLD PR? Thanks.