Why would a system administrator use the tag-switching atm maxhopsgloabal configuration
command?
A.
In large ATM-MPLS networks, the LFIB can become too large. Because of this, it is necessary
to limit the maximum diameter of the MPLS network.
B.
TDP relies exclusively on hop-count carried in the TDP request and replay packets to detect
loops during the downstream-on-demand label allocation.
C.
LDP does not support using Router ID to detect routing information in ATM networks during the
downstream-on demand label allocation process.
D.
Because end-to-end delay can cause problems with some voice applications, it is necessary to
limit the maximum diameter of the MPLS network.
Explanation:
1) According to the “Implementing Cisco MPLS” Student Guide (Text Part Number: 97-1153-01)
Volume 1,
version 1.0, page 6-11. tag-switching atm maxhops: Router ID can be used in LDP to detect
routing
information loops in ATM networks during downstream-on-demand label allocation process. TDP
does not support this option and relies exclusively on hop-count carried in the TDP requests and
reply packets to detect loop during the downstream-on-demand label allocation.
2) According to cisco: see the following website
http://www.cisco.com/en/US/products/sw/iosswrel/ps1828/products_command_reference_chapter
09186a00
tag-switchingatm maxhops To limit the maximum hop counts to a value you have specified, use
the tagswitching
atm maxhops global configuration command. Use the no form of this command to ignore the hop
count.
tag-switchingatm maxhops [number]
notag-switching atm maxhops
Syntax Description
number(Optional) Maximum hop count.Defaults
The default is 254.
Command Modes
Global configuration
Command History
Release Modification 11.1 CTThis command was introduced.Usage Guidelines When an ATM
TSR receives a
BIND REQUEST, it does not send a BIND back if the value in the request is equal to the maxhops
value.
Instead, the ATM TSR or TSR returns an error that specifies that the hop count has been reached.When an ATM-TSR initiates a request for a tag binding, it includes a parameter specifying the
maximum number of hops that the request should travel before reaching the edge of the ATM Tag
Switching region. This is used to prevent forwarding loops in setting up tag paths across the ATM
region.
Examples
The following example sets the hop count limit to 2:
tag-switching atm maxhops 2
Related Commands
Command Description show tag-switching atm-tdp bindingsDisplays the requested entries from
the ATM TDP tag binding database.