Alcatel Carrier Internetworking Solutions 6648 - Manual (Page 375)

OS6624/6648 Architecture
OmniSwitch Troubleshooting Guide September 2005 page -51
VLANs
The IXE2424 supports VLANs based on:
• Ports. This is accomplished using Port Net ID Entry described below.
• 802.1Q Tags. This tag is included in the packet.
• Protocols. This is accomplished using the Protocol to VID Lookup Table described below.
• Addresses. This is accomplished by using the AVID field in NetId (L2, IP or IPX), if Address-based
VLAN feature is enabled.
The VLAN Tag ID (VID) in the Record entry is determined one of two ways
• For a tagged packet VID is the VLAN ID in the tag.
• For an untagged packet, VID is the default VLAN ID associated with the protocol the packet belongs
to. See Protocol Based VLANs description below.
Port Based VLANs
This is the default means of creating VLANs when no other type VLANs (802.1Q for example) has been
programmed. Port Net ID Entry is fetched based on the receive port number. This entry determines the
ports (including CPU) on which the packet received on that port can be transmitted.
Protocol Based VLANs
Can be configured on the IXE2424 by having different protocols point to different VLAN ID Entries
where a VLAN tag is programmed per protocol per port. The IXE2424 supports 19 different Protocol
Based Entries (IP, IPX, ARP etc) including 9 programmable protocols. Protocol to VID Lookup Table
assigns the VID on a per port, per protocol basis. Protocol-based VLAN control bit has to be set for this
feature to work.
Address Based VLANs
Layer 2, IP & IPX NetID entries has AVID (address based vid) field, which is used for untagged packets
as the 802.1Q VLAN ID for all further tag based processing, when Address-based VLAN feature is
enabled.