Cisco WS-X6708-10G-3CXL= - 10 Gigabit Ethernet Module Instrukcja Użytkownika Pobierz pdf (Strona 17)

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src-dst-mac Src XOR Dst Mac Addr

src-dst-mixed-ip-port Src XOR Dst IP Addr and TCP/UDP Port

src-dst-port Src XOR Dst TCP/UDP Port

src-ip Src IP Addr

src-mac Src Mac Addr

src-mixed-ip-port Src IP Addr and TCP/UDP Port

src-port Src TCP/UDP Port

Selection of the hash scheme of choice largely depends on the traffic mix through the Cisco EtherChannel interface,

noting that these hash schemes may be selected only on a global basis.

Determination of Hash Result

With the release of Cisco Virtual Switching System, a new mechanism has been implemented to allow yo u to

determine which physical link a given flow of traffic uses within a port-channel group. You provide inputs to the

command and the hashing algorithm computes the physical link that is selected for the traffic mix and algorithm.

vss#sh etherchannel load-balance hash-result ?

interface Port-channel interface

ip IP address

ipv6 IPv6

l4port Layer 4 port number

mac Mac address

mixed Mixed mode: IP address and Layer 4 port number

mpls MPLS

vss#sh etherchannel load-balance hash-result interface port-channel 120 ip

192.168.220.10 192.168.10.10

Computed RBH: 0x4

Would select Gi1/2/1 of Po120

Adaptive Load Balancing

The addition or removal of a member port from a Cisco EtherChannel interface has always led to a varied amount of

traffic loss for customers. The current generation of port ASICs uses a 3-bit Result Bundle Hash (RBH) value from the

PFC or DFC result to index into a load register to allow a packet to be transmitted if the corresponding bit is set.

When a new port is added or deleted, the load value is reset on all the ports. A new load is then distributed on all the

ports in the Cisco EtherChannel interface, including the new member, and reprogrammed into the port ASIC for each

port. This process causes packets to be dropped during the short outage window (approximately 200 to 300 ms), an

undesirable result for higher-speed interfaces such as 10 Gigabit Ethernet connections where a large amount of

traffic may be lost during this brief outage window.

This problem has led to the development of an enhanced load-distribution mechanism such that when ports are

added or removed from a Cisco EtherChannel interface, the load result does not need to be reset on existing member

ports, resulting in better traffic recovery times.

You can implement this new algorithm either globally or on a per-port channel basis, where fixed is the current

default mode and adaptive uses the enhanced mode:

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Cisco WS-X6708-10G-3CXL= - 10 Gigabit Ethernet Module Instrukcja Użytkownika Strona 17