Cisco Cisco 1700 2600 3600 3700 Series VPN Module 백서
© 2012 Cisco and/or its affiliates. All rights reserved. This document is Cisco Public Information.
Page 16 of 55
Another example of multiple Cisco Virtual Switching System domains is in the area of Layer 2 adjacent WAN
deployments. It may be a requirement for the business or the applications that a routed Layer 3 WAN connection
may not be possible requiring a Layer 2 connection between two disparate geographic sites, yet still providing link
redundancy at the same time. This will ultimately require some form of Layer 2 redundancy protocol be
implemented (such as Spanning Tree Protocol), resulting in complex topologies as well as inefficient bandwidth
utilization across network links. By leveraging Cisco Virtual Switching System, such inefficiencies will be mitigated
through the formation of multichassis Cisco EtherChannel connections.
Cisco EtherChannel Concepts
Cisco EtherChannel interfaces on the Cisco Catalyst 6500 platform represent a grouping of one or more physical
ports into a single, logical port from the perspective of either a Layer 2 switching or Layer 3 routing environment.
Cisco EtherChannel interfaces allow for individual link resiliency as well as providing added bandwidth without the
necessity of complex protocols.
There are generally no restrictions with regard to which ports or modules can form members of a Cisco
EtherChannel link, except that the member interfaces need to be of the same speed and no more than 8 members
can belong to a single Cisco EtherChannel grouping. You can, therefore, extend members of the Cisco
EtherChannel interface across switching modules to allow for the maximum availability of the Cisco EtherChannel
interface if either a single link or module fails.
Traffic Distribution and Hashing
The distribution of traffic across the various members of the Cisco EtherChannel link is accomplished through
different hash schemes, each using a fixed set of fields within the frame to determine which Cisco EtherChannel
member is used to forward a particular traffic flow. With the Supervisor Engine 720-10 G, you can choose from 13
possible different hash schemes:
vss(config)#port-channel load-balance ?
dst-ip Dst IP Addr
dst-mac Dst Mac Addr
dst-mixed-ip-port Dst IP Addr and TCP/UDP Port
dst-port Dst TCP/UDP Port
mpls Load Balancing for MPLS packets
src-dst-ip Src XOR Dst IP Addr
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