Switching Fundamentals Flashcards
What is microsegmentation?
One host, one collision domain.
What are the three actions that a switch can do with a frame?
Forward, filter or flood.
How is a MAC address table built?
With the source MAC addresses of incoming frames.
When will a switch flood a frame?
When the destination MAC address of a frame is not in the switch’s MAC address table.
Unkown unicast frames are always flooded.
Broadcast frames are always flooded.
Multicast frames are always flooded.
When will a switch forward a frame?
When the destination MAC address of a frame is in the switch’s MAC address table.
When will a switch filter a frame?
When the destination MAC address is located on the port that received the frame.
What is the default aging time of the MAC address table?
5 minutes.
Define the CAM table.
Content Addressable Memory table, AKA MAC address table.
Define the TCAM table.
Ternary Content Addressable Memory table. Used in L3 switches.
Define the SDM.
Switching database manager. Divides the switch’s resources based on tasks.
List the basic SDM templates.
Access (ACLs), default, Dual-ipv4-and-ipv6, Routing and VLAN.
Define FLPs.
Fast link pulses. When using auto negotiation, these determine speed and duplex.
Each VLAN is its own ___.
Broadcast domain.
Inter-VLAN traffic requires a ___.
Layer 3 device.
Define a VMPS.
VLAN membership policy server. Used for dynamic VLANs.
How do dynamic VLANs work?
The source address of a frame is matched against a VMPS database to determine the frame’s VLAN. Disables port security.
Define a VVID.
Voice VLAN. A VLAN dedicated to moving voice traffic. Configured on a by-port basis.
Explain how dot1p voice tagging works.
Voice traffic is granted high priority, and is sent through VLAN 0.
Explain how dot1p voice tagging works.
Voice traffic is granted high priority, and is sent through VLAN 0.
Explain how untagged voice tagging works.
Voice traffic is sent through the native VLAN.
Briefly describe ISL.
Inter-Switch Link. Old-school Cisco proprietary. Tags every single frame, with both a header and trailer.
Briefly describe 802.1q.
Dot1q. Standard tagging protocol. Puts a 4-byte tag inside of each frame. Allows native tagging.
What is the MAC range for multicast frames?
0100.5e00.0000-0100.5e7f.ffff
List the three PoE standards and their supported wattage.
802.3af (15.4) 802.3at - PoE+ (25.5) UPoE (60)
Does ISL support untagged frames?
No.
How many bytes does an ISL tag take?
Total of 30 bytes.
How many bytes does a 802.1q encapsulation take?
Total of 4 bytes.
ISL tagging allows for CRC. What is CRC?
Cyclic redundancy check. Allows the frame recipient to test the integrity of the frame based on an algorithm.
The native VLAN is a VLAN designated to send ___ frames on a port-by-port basis.
Untagged.
What happens if the native VLANs on two peer-to-peer trunks mismatch?
The ports will be blocked.
When running “show int trunk”, what does the output “n-“ designate?
The encapsulation type (ISL or 802.1q) was auto-negotiated.
What command can be used to show the status of a switchport mode trunk port that is not currently trunking?
Show interface ___ trunk
How do you hard-code a port to not trunk?
Put it into access mode.
Voice traffic should always be configured using a ___ & ___.
Trunk and VVID.
