RackSwitch G8000 Application Guide

In Figure 3-4, tagged incoming packets are assigned directly to VLAN 2 because of the tag assignment in the packet. Port 5 is configured as a tagged member of VLAN 2, and port 7 is configured as an untagged member of VLAN 2.

Figure 3-4802.1Q tag assignment

 

 

 

PVID = 2

 

 

 

 

 

Tagged packet

 

4

 

 

 

 

 

 

CRC

Data

Tag

SA

DA

 

Port

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Before

Port 1

 

Port 2

 

Port 3

 

802.1Q Switch

 

 

 

 

 

Port 6

 

Port 7

 

Port 8

Port 5

Tagged member of VLAN 2

Untagged member of VLAN 2

BS45013A

As shown in Figure 3-5, the tagged packet remains unchanged as it leaves the switch through port 5, which is configured as a tagged member of VLAN 2. However, the tagged packet is stripped (untagged) as it leaves the switch through port 7, which is configured as an untagged member of VLAN 2.

Figure 3-5802.1Q tagging (after 802.1Q tag assignment)

PVID = 2

Port 4

 

Port 1

 

Port 2

 

Port 3

 

 

 

802.1Q Switch

 

 

 

 

 

 

 

 

Port 6

 

Port 7

 

Port 8

 

Port 5

Tagged member of VLAN 2

CRC Data Tag SA DA

Untagged member

CRC*

(*Recalculated)

of VLAN 2

 

 

 

Data

 

 

SA

Outgoing

 

untagged packet

 

DA

changed

 

(tag removed)

 

 

8100

 

Priority

 

 

CFI

 

VID = 2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

16 bits

 

3 bits

 

 

1 bit

 

12 bits

 

 

 

 

 

 

 

 

 

 

 

 

After

 

 

 

 

 

Key

 

 

 

 

 

 

 

 

 

 

 

Priority

- User_priority

 

 

 

 

 

 

CFI

- Canonical format indicator

 

 

 

VID

- VLAN identifier

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BS45014A

54 „ Chapter 3: VLANs

BMD00041, November 2008

Page 54
Image 54
Blade ICE G8000 manual 4802.1Q tag assignment