Port-Channels - Port-Channels EtherChannels, and NIC Teaming terms used to describe the same function - Regardless of vendor, 802.3ad (LACP) refers to Port-Channeling Used to aggregate bandwidth of multiple physical links between devices - E.g. 4 physical 1GE links would form a 4GE logical Port-Channel Appears as on logic link from STP's protocol In a Data Center it's important to make sure that all links are forwarding and not in a blocked state Port-Channel Load Balancing - Data Flows are load balanced between the member links - Single Flow cannot exceed Bandwidth of any physical member link a.) E.g. increased lanes on the highway but not the speed limit b.) Doen't perform LFI like PPP Multilink See this link for more on MLP and LFI http://www.cisco.com/c/en/us/td/docs/ios/12_2/qos/configuration/guide/fqos_c/qcflem.html#wpxref19484 c.) Still have to do some sort of load balance algorithm - Aggregate of all flows can consume aggregate of PC bandwidth - In the example of 2 10GE links in a port-channel no flow is going to be able to consume more then 10GE at any given time. - Going to be load balanced based on L2, L3, and L4 header information - SRC/DST VLAN, MAC, IP and TCP/UDP port - Default is SRC/DST for L3 IPv4/IPv6 and SR/DST MAC for non IP - This can result in over and under unitized links Configuring Port-Channels - Enable LACP on the switches - config t feature lacp (global command) On routers you cannot use LACP so you need to have the Channel mode on (not active or passive) - On routers it doesn't matter what port-channel # you assign When creating or adding member links to the port-channel you want to disable them first before adding them to the port-channel  N5K1 Conf t feature lacp Routers don't support LACP so no passive or active port-channel mode This is one of the reasons why you wouldn't want to run LACP you can revert these back to a default configuration with config t default int gig0/0 default in gig0/1 int po1 ip address 10.0.0.3 255.255.255.0 int range gig0/0 - 1 channel-group 1 no shut - On the Nexus platforms because of the number of PC you create with vPC and SAN PC's you want to keep track of what PC number are used - You can accomplish this by the " show port-channel usage"  N5K1 You cannot channel the ports together if they have different configurations. conf t int e101/1/1 - 2 shut channel-group 3 mode on no shut int po3 switchport access vlan 10 feature interface-vlan int vlan 10 ip address 10.0.0.51/24 no shut You should be able to ping 10.0.0.3 (router3) Once the port-channels are up run the show port-channel summary  R2 config t default int gig0/0 default in gig0/1 int po1 ip address 10.0.0.2 255.255.255.0 int range gig0/0 - 1 channel-group 1 no shut N5K2 conf t int 102/1/1 - 2 channel-group 1 mode on int po2 switchport access vlan 10 feature interface-vlan int vlan 10 ip address 10.0.0.52/24 no shut N7K1-1 conf t vlan 10 int e2/1 - 4 switchport mode trunk spanning-tree port type network channel-group 1 mode on no shutdown N7K1-2 conf t vlan 10 int e2/9 - 12 switchport mode trunk spanning-tree port type network channel-group 1 mode on no shutdown S1 (IP address 10.0.0.10/24) N5K1 int e101/101/1/4 - 5 channel-group 10 mode active (running LACP) int po10 switchport access vlan 10 show int e101/1/4 - 5  feature LACP int 102/1/6 - 7 channel-group 30 mode active (running LACP) int e102/1/8 - 9 channel-group 40 mode active int po30, po40 switchport access vlan 10 To test links on servers to see if the flows are evenly distributed use the application Iperf When load balancing you want as much information as possible, you would need to change the load balancing method N5K's - port-channel load-balance ethernet source-dest-port N7K's - port-channel load-balance scr-dst ip-l4port-vlan |
Blog >