CCNP switch slides 4 Flashcards
source
http://quizlet.com/3373163/ccnp-switch-deck-4-flash-cards/
what do multilayer switches do?
both layer 2 switching and IVR (inter-vlan routing)
where does L2 switching occur?
between interfaces that are assigned to L2 VLANs or L2 trunks
Where does layer 3 switching occur?
between any type of interface as long as the interface can have an L3 address assigned
what is an SVI?
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
By default, what layer do catalyst switchports operate on?
L2
if the switchport is part of an etherchannel, where is the network assigned
to the virtual port-channel interface
what must be done on an SVI before it is activated?
no shut
What is the traditional MLS view of switching?
route once, switch many
what does the RP do?
receives the first packet of a traffic flow and routes it
what does the SP do?
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
How does the CEF L3 engine operate?
it’s a router that maintains routes (static or dynamic), and populates the FIB
What contains the next-hop entries?
FIB
what does the version number indicate when looking at CEF entries?
the number of times the entry has been updated since the table was generated
what does the epoch number indicate when looking at cef entries?
the number of times the CEF table has bee flushed and regenerated as a whole
what is a CEF punt?
a packet can’t be switched in hardware with the FIB and must go to the L3 engine
what is accelerated CEF (aCEF)?
CEF is distributed across multiple L3 forwarding engines, typically on Catalyst 6500 line cards each having only a subset
what I s distributed CEF (dCEF)?
CEF is distributed completely among multiple L3 forwarding engines.
what is the adjacency table?
a router keeps a routing table and an ARP table. The FIB combines them for every next-hop entry
what is a CEF glean?
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
what is arp throttling?
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
what is a null adjacency?
used to switch packets destined for the null interface
what is a drop adjacency?
used to switch packets that can’t be forwarded normallly due to an encapsulation failure, unresolved address, unsupported protocol, etc.
what is a discard adjacency?
packets are discarded due to an ACL or policy action
