VLAN & Trunking Flashcards
How many CAM tables are on a switch?
One CAM table per VLAN. When a VLAN is created a CAM table is also created.
Fact:
Traffic within the same VLAN must be switched.
Fact:
Traffic outside or between VLAN’s but be routed.
How many bits defines a VLAN?
12 bit field defines a VLAN (2-4094)
Where are VLAN’s Stored
VLAN.DAT file
Normal VLAN Range?
1-1005 1=default 1002/1004=FDDI 1003/1005= Token Ring
What categories do L2 switchports fall into?
Access Ports, Trunk Ports, Dynamic switch ports (DTP).
What are two types of Trunk Encapsulation?
ISL =26byte header & 4 byte trailer encapsulated around the Frame 802.1q=4byte embedded into the Frame
Define and Configure DTP
(config-if)switchport
Dynamic Trunking Protocol. Automatically choose port for Access or Trunk Mode.
What order does DTP try to form?
- Trunk ISL
- Trunk 802.1q
- Access
Describe 802.1q tagging
16 bit = Ethernet Type
3 bit = COS
1 bit CFI
12 bit = VLAN id
Untagged frames are assumed to be the native VLAN. Modifies original Frame. Embedds tagging.
Describe ISL
Does not modify the frame
ISL encapsulates the entire frame
26 byte header & 4 byte trailer (FCS) Double tagging
addes 30bytes to each frame. High overhead.
How do you disable DTP?
switchport no negotiate
or
What are 2 types of Etherchannel?
- PAgP (Cisco Proprietary)
- LACP (IEEE Standard)
What must match between interfaces to form etherchannel?
- Duplex has to be the same.
- Speed has to be there same.
- Same native AND allowed VLANs.
- Same switchport mode (access or trunk).
