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contents
Default:
None.
Command Mode:
Global Mode
Usage Guide:
This command can be used for explaining and describing a prefix-list, e.g.
the application and attention matters of the prefix-list
Example:
Switch#config terminal
Switch(config)#ip prefix-list 3 description This list is used by BGP
14.2.3.2 ip prefix-list seq
Command: ip prefix-list <list_name> [seq <sequence_number>] <deny | permit> <
any | ip_addr/mask_length [ge <min_prefix_len>] [le <max_prefix_len>]>
no ip prefix-list <list_name> [seq <sequence_number>] [<deny | permit> <
any | ip_addr/mask_length [ge <min_prefix_len>] [le <max_prefix_len>]>]
Function:
Configure the prefix-list. The “
no ip prefix-list <list_name> [seq
<sequence_number>] [<deny | permit> < any | ip_addr/mask_length [ge
<min_prefix_len>] [le <max_prefix_len>]>]
” command deletes the prefix-list.
Parameter: <list _name>
is the name of prefix-list, “seq” shows the following
parameters is the sequence number,
<sequence_number>
is the sequence number,
“deny” means deny this route, “permit” means permit this route, “any” means adaptive to
all packets with any prefix as well as any mask length,
ip_addr/mask_length
shows the
prefix address (dotted decimal notation) and the length of mask, “ge” means greater than
or equal to,
<min_prefix_len>
is the minimum length of prefix to be matched
(
ranging
between 0
~
32
)
, “le” means less than or equal to,
<max_prefix_len>
is the maximum
length of prefix to be matched
(
ranging between 0
~
32
)
.
Default:
None.
Command Mode:
Global Mode
Usage Guide:
A prefix-list is identified by a prefix-list name. Each prefix-list may include
several items each of which independently specifies a matching scope of network
prefix-list type which is identified with a
sequence-number. sequence-number
specifies
the sequence of matching check in the prefix-list. In the matching process the switch
check in turn every items identified by “
sequence-number
” ascending. Once certain item
obtains the conditions then the prefix-list filter is passed (without proceeding into the next
item check)
Attentions should be paid on that at least one item match mode should be “permit” when
more than one prefix-list items is defined. The deny mode items can be previously
defined so to remove the unsuitable routing messages fast. However if all items are at
deny mode then none of the routes would be able to pass the filter of this prefix-list. We
here can define a “permit
0.0.0.0/0 ge
0 le
32” item after several defined “deny mode”