Glossary

The suppress-map keyword creates the aggregate route but suppress the advertisement of specified routes. The routes
that are suppressed are not advertised to the neighbors. You can use match clause of route maps to selectively suppress
the specific route from the aggregate routes.
Following is the sample configuration to suppress the advertisement of specific aggregate routes.
DellEMC# configure terminal
DellEMC(conf)# router bgp 100
DellEMC(conf-router_bgp)# aggregate-address 10.1.1.0/24 suppress-map map1
DellEMC(conf-router_bgp)# exit
DellEMC(conf)#
The route-map named map1 can have any action such as permit and sequence number configured, so that the advertisement
of aggregate routes can be suppressed based on the set action in the route-map.
Following is the sample configuration to suppress the advertisement of specific aggregate routes to all neighbors.
DellEMC# configure terminal
DellEMC(conf)# router bgp 100
DellEMC(conf-router_bgp)# aggregate-address 10.1.1.0 255.255.255.0 summary-only
DellEMC(conf-router_bgp)# exit
DellEMC(conf)#
Filtering BGP
The following section describes the methods used to filter the updates received from BGP neighbors.
Following are the filtering methods of BGP updates:
● Filtering using IP prefix lists
● Filtering using route maps
● Filtering using AS-PATH information
● Filtering using community lists
Regular Expressions as Filters
Regular expressions are used to filter AS paths or community lists. A regular expression is a special character used to define a
pattern that is then compared with an input string.
For an AS-path access list, as shown in the previous commands, if the AS path matches the regular expression in the access list,
the route matches the access list.
The following lists the regular expressions accepted in Dell EMC Networking OS.
Regular
Expression
Definition
^ (caret) Matches the beginning of the input string. Alternatively, when used as the first character within brackets
[^ ], this matches any number except the ones specified within the brackets.
$ (dollar) Matches the end of the input string.
. (period) Matches any single character, including white space.
* (asterisk) Matches 0 or more sequences of the immediately previous character or pattern.
+ (plus) Matches 1 or more sequences of the immediately previous character or pattern.
? (question) Matches 0 or 1 sequence of the immediately previous character or pattern.
( ) (parenthesis) Specifies patterns for multiple use when one of the multiplier metacharacters follows: asterisk *, plus sign
+, or question mark ?
[ ] (brackets) Matches any enclosed character and specifies a range of single characters.
- (hyphen) Used within brackets to specify a range of AS or community numbers.
Border Gateway Protocol (BGP) 199