CCNP switch slides 1 Flashcards
Each switch port is a _____ ______
collision domain
What is unknown unicast flooding
MAC addresses are learned from the source MAC of incoming frames. If the destination address is unknown, the frame is flooded out all except the receiving port.
When a host is connected to a switchport, why aren’t frame errors propagated?
because each frame is checked
Where are security and QoS ACLs stored?
TCAM
What is route caching?
The RP listens to a flow’s 1st packet for the dest. The SE listens to the packet and dest and puts a shortcut in the MSL cache. Netflow switching, route once, switch many
What is topology-based caching?
the topology is pre-populated by downloading the topology DB into the FIB and dynamically updated. Called Cisco Express Forwarding
How often are CAM table entries aged?
300 sec
CAM table entries are purged when….
a MAC is seen on a different port
What is the FM?
Feature Manager - after the ACL is created, the FM compiles the ACEs into the table
What is the SDM?
Switching Database Manager - configures and prunes TCAM partitions
What are TCAM entries composed of?
value, mask, and result (VMR) combinations
What is the size of a TCAM value?
134 bits, consisting of source and destination addresses and protocol information from the packet or frame
How long are TCAM masks?
134 bits
What are LOU register pairs?
used when ACLs specify port ranges…used by TCAM
What is a 10GE WAN PHY?
Connects with SONET or SDH
What pins does FE use?
1/2 and 3/6
What cabling do GBICs use?
SC fiber or RJ-45
Which fiber is the receive?
on the left as you face the connector
What types of ports autonegotiate?
FE and GE
What is the default 10mbps Enet duplex?
half-duplex
What is the default FE duplex?
Full duplex
How are errdisable triggers tuned?
globally
what is errdisable dtp-flap?
change in trunk encap
what is errdisable pagp-flap?
etherchannel ports have inconsistent config
How do you renable an err-disable port by default?
manually
If a port is configured for errdisable auto recovery, how long does it stay down?
300 sec by default
How do you find duplex mismatches?
use sh interface on the interface and look for error counts > 10
what is a vlan?
a single broadcast domain
static vlans offer ____ based membership
port
the static port to vlan membership is handled in _____
the ASIC
What is the default MTU?
1500B
What is the acceptible range of VLANS?
1-1005 (1 and 1002-1005 are reserved)
What are dynamic VLANs based on?
MAC of the end device
One vlan should =
1 IP subnet
What is an end to end vlan?
a VLAN that spans the entire fabric
What is the 80/20 rule?
80% of the user traffic should stay in the VLAN
How does ISL do framing on trunks?
by encapsulating each frame in a header and trailer
What types of links can be trunked?
FE, GE, and aggregated FE/GE Etherchannels
How does dot1q do framing on trunks?
embeds the tag within the frame
What is the size of ISL encapsulation?
26-byte header, 4-byte trailer with CRC
What is a baby giant frame?
frames that barely exceed 1518B or 1622B due to headers
What does DTP do?
automatically negotiates a common trunk mode between switches
What are the 3 trunk encap modes?
isl, dot1q, negotiate (default
What are the 3 trunk switchport modes?
trunk, dynamic auto, dynamic desireable (default)
what is dynamic desireable?
the port asks the other end to trunk
what is dynamic auto?
will trunk if asked
How do you disable DTP when you configure both ends of the ISL manually?
switchport nonegotiate
Which 4 things must be agreeable to trunk?
1- trunking mode, 2-trunk encapsulation, 3-native VLAN, 4-allowed VLAN
What is the default VTP state?
VTP server for domain null with no password or secure mode
What are 2 ways to configure VLAN and VTP information?
Global config (vlan, vtp mode, and vtp domain) and VLAN DB mode commands. Global config is preferred because VLAN DB mode commands are legacy
