CCNP switch slides 4

Question 1

source

Answer 1

http://quizlet.com/3373163/ccnp-switch-deck-4-flash-cards/

Question 2

what do multilayer switches do?

Answer 2

both layer 2 switching and IVR (inter-vlan routing)

Question 3

where does L2 switching occur?

Answer 3

between interfaces that are assigned to L2 VLANs or L2 trunks

Question 4

Where does layer 3 switching occur?

Answer 4

between any type of interface as long as the interface can have an L3 address assigned

Question 5

what is an SVI?

Answer 5

Switched Virtual Interface - an L3 address can be assigned to a logical interface that represents an entire VLAN, which becomes the DGW for that VLAN

Question 6

By default, what layer do catalyst switchports operate on?

Answer 6

L2

Question 7

if the switchport is part of an etherchannel, where is the network assigned

Answer 7

to the virtual port-channel interface

Question 8

what must be done on an SVI before it is activated?

Answer 8

no shut

Question 9

What is the traditional MLS view of switching?

Answer 9

route once, switch many

Question 10

what does the RP do?

Answer 10

receives the first packet of a traffic flow and routes it

Question 11

what does the SP do?

Answer 11

listens to the first packet going to router and away from the router. If it can switch in both directions, it learns a shortcut path so subsequent packets can be switched without the RP

Question 12

How does the CEF L3 engine operate?

Answer 12

it’s a router that maintains routes (static or dynamic), and populates the FIB

Question 13

What contains the next-hop entries?

Answer 13

FIB

Question 14

what does the version number indicate when looking at CEF entries?

Answer 14

the number of times the entry has been updated since the table was generated

Question 15

what does the epoch number indicate when looking at cef entries?

Answer 15

the number of times the CEF table has bee flushed and regenerated as a whole

Question 16

what is a CEF punt?

Answer 16

a packet can’t be switched in hardware with the FIB and must go to the L3 engine

Question 17

what is accelerated CEF (aCEF)?

Answer 17

CEF is distributed across multiple L3 forwarding engines, typically on Catalyst 6500 line cards each having only a subset

Question 18

what I s distributed CEF (dCEF)?

Answer 18

CEF is distributed completely among multiple L3 forwarding engines.

Question 19

what is the adjacency table?

Answer 19

a router keeps a routing table and an ARP table. The FIB combines them for every next-hop entry

Question 20

what is a CEF glean?

Answer 20

the L3 forwarding engine can’t forward the packet in hardware because there is no L2 next-hop address, so the packet is sent to the L3 engine to generate the ARP response

Question 21

what is arp throttling?

Answer 21

during the time that the FIB entry is in CEF glean waiting for ARP entries, subsequent packet to that host are dropped to keep input queues from filling

Question 22

what is a null adjacency?

Answer 22

used to switch packets destined for the null interface

Question 23

what is a drop adjacency?

Answer 23

used to switch packets that can’t be forwarded normallly due to an encapsulation failure, unresolved address, unsupported protocol, etc.

Question 24

what is a discard adjacency?

Answer 24

packets are discarded due to an ACL or policy action

Question 25

what is a punt adjacency?

Answer 25

packets must be sent to the L3 engine for further processing

Question 26

what does the rewrite engine do?

Answer 26

it updates the L2 headers with the proper src and dst MAC, L3 TTL, L3 checksum, and L2 checksum information

Question 27

How do you enable CEF?

Answer 27

it is enabled by default on all CEF capable switches

Question 28

What are the 4 steps in DHCP negotiation?

Answer 28

1-client sends DHCP discover as broadcast, 2-DHCP server sends DHCP offer, client sends DHCP Request, DHCP server sends DHCP ack

Question 29

How do you configure a DHCP gateway?

Answer 29

first configure a L3 interface in same VLAN as clients, then use the ip helper-address command to ID the DHCP server

Question 30

What are the characteristics of the access layer?

Answer 30

low cost, high density ports, multiple scalable uplinks, vlans, traffic and protocol filtering and QoS

Question 31

What are the characteristics of the distribution layer?

Answer 31

aggregation, high L3 throughput, security and policy based connectivity functions through access lists and packet filters, QoS, scalable high-speed links

Question 32

what are the characteristics of the core layer

Answer 32

Very high L3 throughput, no access lists or port filtering, redundancy and resilience, advanced QoS

Question 33

What is the core block?

Answer 33

the campus network’s backbone

Question 34

What is the switch block?

Answer 34

Two distribution switches that aggregate one or more access switches

Question 35

Where should multilayer switches be implemented?

Answer 35

Distribution layer

Question 36

How far chould a VLAN extend?

Answer 36

Distribution layer

Question 37

What criteria are used to size a switch block?

Answer 37

traffic types and patterns, amount of L3 switching cap. At dist. Layer, # users at access layer, geography, size of spanning tree domains

Question 38

How many users should be within a switch block?

Answer 38

roughly 2000

Question 39

How can you tell if a switch block is too large?

Answer 39

Routers at the distribution layer become the bottlenecks or broadcast or multicast traffic slows the switches in the switch block

Question 40

What is the access layer best practice?

Answer 40

All L2 connectivity should be contained within the access layer.

Question 41

What is the distribution layer best practice?

Answer 41

The distribution layer should have only L3 links