MPLS transit load balancing

A hashing scheme for enhanced load balancing allows MPLS transit load balancing to include inner headers of different packet types in parallel. With this enhanced load balancing scheme, SLX-OS is capable of load balancing the MPLS packets based on the inner headers like Inner source/destination mac address, Inner IPv4 source/destination address, Inner IPv6 source/destination address, Inner L4 port number if the inner header is IPv4.

Note

MPLS transit load balancing is not supported only on devices based on the DNX chipset family. For a list of these devices, see Supported Hardware.

This hashing scheme is supported only with the "Layer 2 Optimized" Tcam profile and when the feature is enabled by default in this profile. When the profile tcam layer2-optimised-1 configuration is activated, the "Error: Operation not supported in the current hardware TCAM profile" message is displayed for the following commands as these functionalities are already taken care of by this enhanced hashing scheme:

lag hash speculate-mpls inner-eth
lag hash speculate-mpls inner-ip-raw
lag hash speculate-mpls inner-ip-tag
lag hash speculate-mpls inner-ipv6-raw
lag hash speculate-mpls inner-ipv6-tag

Displaying LAG hashing with "Layer 2 Optimized" Tcam profile

Use the show port-channel load-balance command to display the configured parameters for LAG hashing when the profile tcam layer2-optimised-1 configuration is activated.

device# show port-channel load-balance
Header parameters
        Ethernet Mask: sa-mac da-mac etype vlan
        ip: src-ip dst-ip protocol src-l4-port dst-l4-port
        ipv6: ipv6-src-ip ipv6-dst-ip ipv6-next-hdr ipv6-src-l4-port ipv6-dst-l4-port
        mpls: label1 label2 label3

Hash Settings
        hdr-start:FWD, hdr-count:3, bos-start:0, bos-skip:0, skip-cw:0
        normalize:0, rotate:3, include_src_port:0, Disable: L2 0, ipv4 0, ipv6 0, mpls 0

mpls_speculate: Enabled

Inner Header parameters for MPLS packets
                Ethernet Mask: Selective 64 bits from sa-mac da-mac vlan
                ip: src-ip dst-ip src-l4-port dst-l4-port
                ipv6: ipv6-src-ip ipv6-dst-ip

load-balance-type hash-based

For comparison, the following displays the show port-channel load-balance command output for a non layer 2 optimized profile:

device# show port-channel load-balance 
Header parameters
        Ethernet Mask: sa-mac da-mac etype vlan 
        ip: src-ip dst-ip protocol src-l4-port dst-l4-port 
        ipv6: ipv6-src-ip ipv6-dst-ip ipv6-next-hdr ipv6-src-l4-port ipv6-dst-l4-port 
        mpls: label1 label2 label3 

Hash Settings
        hdr-start:FWD, hdr-count:1, bos-start:0, bos-skip:0, skip-cw:0 
        normalize:0, rotate:3, include_src_port:0, Disable: L2 0, ipv4 0, ipv6 0, mpls 0
 
mpls_speculate:Enabled

load-balance-type hash-based