3Com 9100 Switch User Manual


 
154
A
PPENDIX
C: T
ROUBLESHOOTING
which should now allow you to re-enter the previous command without
error as follows:
localhost:26 # config vlan red add port 1,2
VLAN names:
There are restrictions on VLAN names. They cannot contain whitespaces
and cannot start with a numeric value unless you use quotation marks
around the name. If a name contains whitespaces, starts with a numeric,
or contains non-alphabetical characters, you must use quotation marks
whenever referring to the VLAN name.
802.1Q links do not work correctly:
Remember that VLAN names are only locally significant through the
command-line interface. For two switches to communicate across a
802.1Q link, the VLAN ID for the VLAN on one switch should have a
corresponding VLAN ID for the VLAN on the other switch.
If you are connecting to a third-party device and have checked that the
VLAN IDs are the same, the Ethertype field used to identify packets as
802.1Q packets may differ between the devices. The default value used
by the switch is
8100
. If the third-party device differs from this and
cannot be changed, you may change the 802.1Q Ethertype used by the
switch with the following command:
config dot1p ethertype <ethertype>
Changing this parameter changes how the system recognizes all tagged
frames received, as well as the value it inserts in all tagged frames it
transmits.
VLANs, IP Addresses and default routes:
The system can have an IP address for each configured VLAN. It is only
necessary to have an IP address associated with a VLAN if you intend to
manage (Telnet, SNMP, ping) through that VLAN. You can also configure
a default gateway.