Etherchannel - Cisco NM-8B-U - HW ROUTERS L-M User Manual

16- and 36-Port Ethernet Switch Module for Cisco 2600 Series, Cisco 3600 Series, and Cisco 3700 Series
VTP Version 2
If you use VTP in your network, you must decide whether to use VTP version 1 or version 2. VTP
version 2 supports the following features not supported in version 1:
Unrecognized Type-Length-Value (TLV) Support—A VTP server or client propagates configuration
changes to its other trunks, even for TLVs it is not able to parse. The unrecognized TLV is saved in
NVRAM.
Version-Dependent Transparent Mode—In VTP version 1, a VTP transparent switch inspects VTP
messages for the domain name and version, and forwards a message only if the version and domain name
match. Since only one domain is supported in the NM-16ESW software, VTP version 2 forwards VTP
messages in transparent mode, without checking the version.
Consistency Checks—In VTP version 2, VLAN consistency checks (such as VLAN names and values)
are performed only when you enter new information through the CLI or SNMP. Consistency checks are
not performed when new information is obtained from a VTP message, or when information is read from
NVRAM. If the digest on a received VTP message is correct, its information is accepted without
consistency checks.
VTP Configuration Guidelines and Restrictions
Follow these guidelines and restrictions when implementing VTP in your network:
•
•
•
•
•
•
•

EtherChannel

EtherChannel bundles up to eight individual Ethernet links into a single logical link that provides
bandwidth of up to 1600 Mbps (Fast EtherChannel full duplex) between the network module and another
switch or host.
A Ethernet switch network module system supports a maximum of six EtherChannels. All interfaces in
each EtherChannel must have the same speed duplex and mode.
Load Balancing
EtherChannel balances traffic load across the links in a channel by reducing part of the binary pattern
formed from the addresses in the frame to a numerical value that selects one of the links in the channel.
EtherChannel load balancing can use MAC addresses, or IP addresses; either source or destination or
both source and destination. The selected mode applies to all EtherChannels configured on the switch.
All switches in a VTP domain must run the same VTP version.
You must configure a password on each switch in the management domain when in secure mode.
A VTP version 2-capable switch can operate in the same VTP domain as a switch running VTP
version 1, provided that VTP version 2 is disabled on the VTP version 2-capable switch. (VTP
version 2 is disabled by default).
Do not enable VTP version 2 on a switch unless all switches in the same VTP domain are version
2-capable. When you enable VTP version 2 on a switch, all version 2-capable switches in the domain
enable VTP version 2
The Cisco IOS end and Ctrl-Z commands are not supported in VLAN database mode.
The VLAN database stored on internal flash is supported.
Use the squeeze flash command to remove old copies of overwritten VLAN databases.
Cisco IOS Release 12.2(2)XT, 12.2(8)T, and 12.2(15)ZJ
Feature Overview
7