Information on ISL header... taken from
http://www.cisco.com/warp/public/741/4.html
VLAN - Virtual LAN ID
The VLAN field is the virtual LAN ID of the packet. It is a 15-bit value
that is used to distinguish frames on different VLANs. This field is often
referred to as the "color" of the packet.
Information on 802.1Q packet... taken from
http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121newft/121
t/121t3/dtbridge.htm#xtocid114535
The tag is stored in the following two octets and it contains 3 bits of user
priority, 1 bit of Canonical Format Identifier (CFI) and 12 bits of VLAN ID
(VID). The 3 bits of user priority are used by the standard 802.1p; and the
CFI is used for compatibility reasons between Ethernet type networks and
Token Ring type networks. The VID is the identification of the VLAN, which
is basically used by the standard 802.1Q and, being on 12 bits, it allows
the identification of 4096 VLANs.
Brant I. Stevens
Internetwork Solutions Engineer
Thrupoint, Inc.
545 Fifth Avenue, 14th Floor
New York, NY. 10017
646-562-6540
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of
Gopinath Pulyankote
Sent: Wednesday, February 28, 2001 1:49 PM
To: [EMAIL PROTECTED]
Subject: BCMSN: VLAN ID How many bits? 10 or 15 ??
Hi all,
The Cisco Press book BCMSN by Karen Webb says the VLAN ID is 15 bits,
but I read somewhere else its 10 bits.
Which is correct ??
TIA
--Gopinath
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