By default, when does a Cisco router switch over from the root-path-tree to the source-specific SPT?
Highlight for answer: When the first packet is received from the shared tree. You can change this with the ‘ip pim spt-threshold’ command.
August 6, 2009
July 15, 2009
Core Knowledge Question of the Day: 15 July 2009
A port in the Spanning Tree state of ‘blocking’ does not allow any type of traffic – true or false?
Highlight for answer: False – BPDUs are still allowed over the link.
July 7, 2009
Core Knowledge Question of the Day: 07 July 2009
What is the effect of issuing the exec level command ‘terminal monitor’?
Highlight for answer: This command will enable the device to send log messages to telnet sessions.
July 6, 2009
Core Knowledge Question of the Day: 06 July 2009
What are unsolicited messages sent from an SNMP agent to an SNMP management station called?
Highlight for answer: SNMP traps. SNMP informs fit this description as well.
June 26, 2009
Core Knowledge Question of the Day: 26 June 2009
What is the name of a well-known discretionary BGP attribute that is used to alert downstream routers that a loss of path information has occurred?
Highlight for answer: ATOMIC_AGGREGATE.
June 24, 2009
Core Knowledge Question of the Day: 24 June 2009
What is the practice of advertising a contiguous set of addresses with a single, less-specific address called?
Highlight for answer: Summarization or route aggregation
June 15, 2009
Core Knowledge Question of the Day: 15 June 2009
Which two commands can be used to disable the executive timeout feature?
Highlight for answer: no exec-timeout or exec-timeout 0 0
June 2, 2009
Core Knowledge Question of the Day: 02 June 2009
An OSPF virtual-link is a link to the backbone area through….
Highlight for answer: a nonbackbone(transit), non-stub area.
June 1, 2009
Core Knowledge Question of the Day: 01 June 2009
When configuring OSPF Fast Hello Packets, does the hello multiplier need to match on the entire segment?
Highlight for answer: Not as long as at least one hello packet is sent within the dead-interval (1 second).
May 27, 2009
Core Knowledge Question of the Day: 27 May 2009
R3#sh frame map
Serial0/0 (up): ip 155.3.0.3 dlci 503(0x1F7,0x7C70), static,
broadcast,
CISCO, status defined, active
TCP/IP Header Compression (inherited), connections: 218959117
RTP Header Compression (inherited), connections: 218959117
R5#sh frame map
Serial1/0 (up): ip 155.1.0.5 dlci 305(0x131,0x4C10), static,
broadcast,
CISCO, status defined, active
TCP/IP Header Compression (enabled), connections: 256
RTP Header Compression (enabled), connections: 256
Given the above output, what is the fundamental difference between the TCP and RTP header compression configurations on R3 and R5?
Highlight for answer: On R3, TCP and RTP header compression have been enabled on the interface level as indicated by the ‘inherited’ description in the ‘show frame-relay map’ output. On R5 it has been enabled via the frame-relay map map statement(with the keyword ‘compress’).
