The 7705 SAR supports load balancing based on service ID, as shown in Table: Hashing Algorithm Inputs (ECMP and LAG) , The 7705 SAR uses the service ID as the input to the hash function. Per-service and per-flow hashing are mutually exclusive features.
For IPv4 and IPv6 routed traffic under ECMP operation, the service ID is used as the hashing input for Layer 3 traffic going to a Layer 3 spoke SDP interface. Otherwise, per-flow load balancing is used.
For Epipe and VPLS services under LAG operation, the per-service-hashing command and the l4-load-balancing and teid-load-balancing commands are mutually exclusive. Load balancing via per-service hashing is configured under the config>service> epipe>load-balancing and config>service>vpls> load-balancing contexts.
If per-service-hashing is not enabled, a 4-byte hash value will be appended to internal overhead for VPLS multicast traffic at ingress. The egress internal hash value is discarded at egress before scheduling. Therefore, shaping rates at access and network ingress and for fabric policies may need to be adjusted accordingly. In addition, the 4-byte internal hash value may be included in any affected statistics counters.
The 7705 SAR supports multiple LSPs (RSVP-TE or segment routing TE (SR-TE)) in the same SDP as part of the mixed-LSP SDP feature (refer to the ‟Mixed-LSP SDPs” section in the 7705 SAR Services Guide for details). When an SDP is configured with multiple LSPs of the same type, it allows load balancing of the traffic in a similar manner as load balancing for LDP ECMP, but only at the iLER point. Therefore, the per-flow hashing and per-service hashing behavior described in this section for LDP ECMP at the iLER also applies to multiple LSPs (RSVP-TE or SR-TE) in the same SDP.