1Net::BGP::ASPath(3) User Contributed Perl Documentation Net::BGP::ASPath(3)
2
6 "Net::BGP::ASPath" - Class encapsulating BGP-4 AS Path information
7
9 use Net::BGP::ASPath;
10 # Constructor
12 $aspath = Net::BGP::ASPath->new(undef, { as4 => 1 });
13 $aspath2 = Net::BGP::ASPath->new([65001,65002]);
14 $aspath3 = Net::BGP::ASPath->new("(65001 65002) 65010");
15 $aspath4 = Net::BGP::ASPath->new("65001 {65011,65010}");
16 # Object Copy
18 $clone = $aspath->clone();
19 # Modifiers;
21 $aspath = $aspath->prepend(64999);
22 $aspath = $aspath->prepend("64999 65998");
23 $aspath = $aspath->prepend([64999,65998]);
24 $aspath = $aspath->prepend("(64999 65998)");
26 $aspath = $aspath->prepend_confed("64999 65998");
27 $aspath += "65001 65002"; # Same as $aspath->prepend("65001 65002")
29 $aspath5 = $aspath->striped; # New object
31 $aspath = $aspath->strip; # Same modified
32 $aspath = $aspath->cleanup # Same modified
34 # Aggregation
36 $aspath = $aspath1->aggregate($aspath2,$aspath3);
37 $aspath = Net::BGP::ASPath->aggregate($aspath1,$aspath2,$aspath3);
38 # Accessor Methods
41 $length = $aspath->length;
42 $string = $aspath->as_string;
43 $array_ref = $aspath->asarray
44 # In context
46 $string = "The AS path is: " . $aspath;
47 $firstas = $aspath[0];
48 # Length comparisons
50 if ($aspath < $aspath2) { ... };
51 if ($aspath > $aspath2) { ... };
52 if ($aspath == $aspath2) { ... };
53 if ($aspath != $aspath2) { ... };
54 @sorted = sort { $a <=> $b } ($aspath, $aspath2, $aspath3, $aspath4);
55 # Path comparisons
57 if ($aspath eq $aspath2) { ... };
58 if ($aspath ne $aspath2) { ... };
59
61 This module encapsulates the data contained in a BGP-4 AS_PATH,
62 including confederation extensions.
63
65 new() - create a new "Net::BGP::ASPath" object
66 $aspath = Net::BGP::ASPath->new( PATHDATA, OPTIONS );
67 This is the constructor for "Net::BGP::ASPath" objects. It returns
69 a reference to the newly created object. The first parameter may be
70 either:
71 ARRAY_REF
73 An array ref containing AS numbers interpreted as an
74 AS_PATH_SEQUENCE.
75 SCALAR
77 A string with AS numbers separated by spaces
78 (AS_PATH_SEQUANCE). AS_PATH_SETs are written using "{}" with
79 "," to separate AS numbers. AS_PATH_CONFED_* is written
80 similarly, but encapsulated in "()".
81 "Net::BGP::ASPath"
83 Another ASPath object, in which case a clone is constructed.
84 "undef"
86 This will create the ASPath object with empty contents.
87 Following the PATHDATA, the OPTIONS may be specified. Currently
89 the only valid option is c<as4>, which, if true, builds ASPath
90 objects usable for talking to a peer that supports 32 bit ASNs.
91 False, or the default value, assumes that the peer does not support
92 32 bit ASNs, which affects the decode routines. Note that the
93 encode routines are not dependent upon this option.
94 Basically, if as4 is true, AS_PATH is populated from messages
96 assuming 4 byte ASNs and AS4_PATH is not used. Encoded AS_PATH
97 attributes also assume a 4 byte ASN.
98 If as4 is false, AS_PATH is populated from messages assuming 2 byte
100 ASNs, and, if available, AS4_PATH is used to replace occurences of
101 23456 when possible when outputing to user-readable formats.
102 Encoding routines will also allow output of AS4_PATH objects when
103 appropriate.
104
106 clone() - clone a "Net::BGP::ASPath" object
107 $clone = $aspath->clone();
108 This method creates an exact copy of the "Net::BGP::ASPath" object.
110
112 length()
113 Return the path-length used in BGP path selection. This is the sum
114 of the lengths of all AS_PATH elements. This does however not
115 include AS_PATH_CONFED_* elements and AS_SEGMENTS which count as
116 one BGP hop.
117 as_string()
119 Returns the path as a string in same notation that the constructor
120 accepts.
121 cleanup()
123 Reduce the path by removing meaningless AS_PATH elements (empty
124 sets or sequences) and joining neighbor elements of the same _SET
125 type.
126 strip()
128 Strips AS_CONFED_* segments from the path.
129 striped()
131 Returns a strip() 'ed clone() of the path.
132 prepend(ARRAY)
134 prepend(SCALAR)
135 Strips AS_CONFED_* segments from the path and prepends one or more
136 AS numbers to the path as given as arguments, either as an array of
137 AS numbers or as a string with space separated AS numbers. If the
138 string has "()" surrounding it, prepend_confed will be used
139 instead.
140 prepend_confed(ARRAY)
142 prepend_confed(SCALAR)
143 Prepends one or more confederation AS numbers to the path as given
144 as arguments, either as an array of AS numbers or as a string with
145 space separated AS numbers. "()" around the string is ignored.
146 aggregate(ASPath)
148 aggregate(ARRAY)
149 Aggregates the current ASPath with the ASPath(s) given as argument.
150 If invoked as a class method, aggregate all ASPaths given as
151 argument.
152 To aggregate means to find the longest common substring (of the
154 paths of all objects that should be aggregated) and keep them, but
155 replacing the non-common substrings with AS_SET segments. Currently
156 only the longest common normal and confederation head will be found
157 and the remaining will be left as an AS_SET and AS_CONFED_SET.
158 Returns the aggregated object. The objects themselves are not
160 modified.
161
163 Net::BGP
164 Net::BGP::Process
165 Net::BGP::Peer
166 Net::BGP::Update
167 Net::BGP::Refresh
168 Net::BGP::NLRI
169 Net::BGP::Notification
170
172 Martin Lorensen <bgp@martin.lorensen.dk>
173perl v5.36.0 2022-07-22 Net::BGP::ASPath(3)