Brocade Communications Systems RFS6000 - Manual (Page 421)

Brocade Mobility RFS4000, RFS6000 and RFS7000 CLI Reference Guide 419
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Interface config commands
12
3. Select the other interface required for port aggregation and associate the static channel group
to it.
RFController(config)#interface ge 2
RFController(config-if)#static-channel-group 1
4. Execute
show static-channel-group
and ensure the virtual static aggregation
sa 1 has been created and associated with
ge 2.
Both ge 1 and ge 2 are now aggregated and ready for use.
5. Use the
port-channel
command to select the criteria used to determine which link is selected
for a given packet. The port-channel selection is based on either source-destination IP or
source destination MAC
RFController(config-if)#port-channel load-balance src-dst-ip
RFController(config-if)#
The default port-channel criteria is based on source-destination IP. The port channel (when
configured with
src-dst-ip)
does not show up in the running-config. Hence, this mode is preferred
over
src-dst-mac.
NOTE
When a port (GE) is aggregated into a Static Aggregation (SA), it temporarily takes on the port
configuration of the SA.
For example, If GE 1 (previously configured as trunk vlan 1-10) and GE 2 (previously configured as
trunk vlan 11-20) are now aggregated as SA 1 and SA 1 is configured as trunk vlan 100-200, then
SA 1’s configuration applies to both GE 1 and GE 2. This new configuration like VLAN, speed,
duplex, MST is now applicable on the ports as long as they are part of the SA. The ports revert back
to the original configuration once they are removed from the SA.
How src-dst-mac mode works
When the controller sends a packet out of a SA, it selects the egress port as a function of the
packet's source MAC, destination MAC, and the set of ports in the SA which are running. It XORs the
bottom bits of the two MACs and indexes it into a table of the running ports.
How src-dst-ip mode works
When the controller sends an IP packet, the egress port is chosen as a function of the packet's
source IP, destination IP and the set of running ports. It XORs the bottom byte of the two IP
addresses and indexes then into the same table of running ports that
src-dst-mac
mode uses.
If the packet is NOT an IP packet, it uses the same calculation as src-dst-mac mode.
Why is src-dst-ip mode preferred
src-dst-ip mode distributes packets better when most packets, going through the gateway, are IP
packets. In the presence of an IP gateway, the IP packets forwarded from one Client to hosts that is
beyond the gateway all have the same MAC pair <Client MAC, Gateway MAC> no matter what host
the Client is accessing.
But in src-dst-mac balancing, the same link is selected always.