AS16509 peering information and eBGP neighbors

interconnection points


Extensive peering arrangements are a critical component to providing outstanding connectivity and performance for the customers as well as increased service resilience through diversified routing.

Peering is the bedrock of every network and all service providers actively expand their peering capacity in line with traffic growth to maintain world class performance.

AS16509 Configuration for iBGP and eBGP

BGP is an exterior gateway protocol (EGP), used to perform interdomain routing in TCP/IP networks. A BGP router needs to establish a connection (on TCP port 179) to each of it's BGP peers before BGP updates can be exchanged. The BGP session between two BGP peers is said to be an external BGP (eBGP) session if the BGP peers are in different autonomous systems (AS). A BGP session between two BGP peers is said to be an internal BGP (iBGP) session if the BGP peers are in the same AS16509 autonomous system.

By default, the peer relationship is established using the IP address of the interface closest to the peer router. However, using the neighbor update-source command, any operational interface, including the loopback interface, can be specified to be used for establishing TCP connections. This method of peering using a loopback interface is useful since it will not bring down the BGP session when there are multiple paths between the BGP peers, which would otherwise result in tearing down the BGP session if the physical interface used for establishing the session goes down. In addition to that, it also allows the routers running BGP with multiple links between them to load balance over the available paths.

AS16509 Network Diagram

The AS16509 backbone cost burden associated with settlement-free peering traffic exchange should be equitably shared. Regardless of the direction or type of traffic exchanged between the networks, the routing practices and location or interconnection points should be such that each party bears a reasonably equal share of backbone costs.

In the case that the peering party has significant excess inbound traffic volume to deliver to AS16509 (significantly in excess of that being sent outbound by AS16509 to that party) then the parties should agree the routing behaviour expected of one another within reasonable technical, and operationally-feasible bounds.

When the peering partner has network presence in multiple countries or continents where AS16509 also has Points Of Presence, it will be desirable to open peering legs in at least two locations, and maybe more, subject to the cost/benefits of PoP build-out. This is to ensure that the traffic is exchanged optimally in the respective countries/continents and peering interconnections benefit both partners equally.

Peers must be directly connected when using eBGP. If they are not directly connected, the neighbor ebgp-multihop command must be used and a path through an IGP or static route to reach the peer must exist in order for the routers to establish neighbor relationship.

Verify iBGP/eBGP AS16509 Configuration

Use the show ip bgp neighbors command to display information about the TCP and Border Gateway Protocol (BGP) connections and verify if the BGP peer is established. The output of the show ip bgp neighbors command below shows the BGP state as 'Established', which indicates that the BGP peer relationship has been established successfully.

R1-AGS# show ip bgp neighbors | include BGP
BGP neighbor is 10.10.10.2,  remote AS 16509, internal link
  BGP version 4, remote router ID 2.2.2.2
  BGP state = Established, up for 00:04:20
  BGP table version 1, neighbor version 1
R1-AGS#

The show ip bgp neighbors command has been used above with the modifier | include BGP. This makes the output more readable by filtering the the command output and displaying the relevant parts only.

In addition, the show ip bgp summary command can also be used to display the status of all BGP connections, as shown below.

R1-AGS(9)# show ip bgp summary
BGP router identifier 10.1.1.2, local AS number 16509	
BGP table version is 1, main routing table version 1

Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
10.10.10.2      4 16509       3       3        1    0    0 00:00:26        0

AS16509 eBGP Configuration with a Loopback Address

You can also configure eBGP/iBGP using a loopback address (or any other operational interface). Loopback interfaces are used in this manner to guarantee reachability in networks with multiple paths as shown in Sample Configurations of the Load Sharing Using the Loopback Address as a BGP Neighbor section of Load Sharing with BGP in Single and Multihomed Environments.

Load balancing with Multihomed AS16509 to Two ISPs Through a Single Local Router

This case shows how to achieve load sharing when multiple links exist between a remote AS and AS16509. These links are terminated in one router at the AS16509 and on multiple routers at remote ASs in a single-homed BGP environment.


ASN IPv4 IPv6 Power
AS1103           692       206       3  
AS11096           342       0       2  
AS11404           35       0       1  
AS11537           301       0       4  
AS1221           19       36       8  
AS12389           692       0       2  
AS1239           3       0       1  
AS12552           528       0       1  
AS1257           644       41       2  
AS1267           182       0       2  
AS1273           4895       901       18  
AS12874           287       165       3  
AS12956           11731       1841       27  
AS1299           126493       20334       768  
AS13030           14509       3378       55  
AS13193           0       20       1  
AS132132           423       0       3  
AS136620           170       2       2  
AS14586           360       0       19  
AS15576           2       0       2  
AS15704           195       0       1  
AS16735           3093       36       12  
AS174           104360       13386       539  
AS1764           0       72       1  
AS1836           2984       1134       9  
AS1853           523       169       2  
AS19151           3208       126       6  
AS1916           997       258       7  
AS196753           553       208       4  
AS197595           39       0       1  
AS198385           1178       484       4  
AS198507           2       186       2  
AS20080           1401       63       6  
AS20485           970       396       8  
AS20562           2100       0       6  
AS20764           1229       492       4  
AS209           2641       66646       569  
AS20965           622       223       2  
AS2119           149       0       1  
AS21320           260       22       2  
AS22356           1270       0       3  
AS22773           12       0       6  
AS23252           12       0       6  
AS23520           766       63       3  
AS24115           279       0       1  
AS24130           1       0       1  
AS24218           19       0       3  
AS24811           607       0       2  
AS24961           2485       8       8  
AS2497           6942       2647       9  
AS25091           3730       0       4  
AS2516           1195       0       6  
AS25512           1       0       1  
AS2603           896       29       6  
AS262589           14       0       1  
AS2852           12       0       1  
AS286           2552       665       8  
AS28716           522       0       2  
AS29075           27       0       1  
AS2914           104383       29666       661  
AS29208           125       0       2  
AS29632           0       430       2  
AS29691           1072       192       5  
AS30781           369       0       4  
AS31133           3018       0       3  
AS31424           782       438       4  
AS31500           246       0       1  
AS3216           1471       0       5  
AS3223           1423       0       3  
AS3257           45270       10568       491  
AS3267           531       0       2  
AS328145           0       3       1  
AS3303           549       80       4  
AS3320           729       1271       19  
AS3356           53285       3670       314  
AS33891           4963       867       28  
AS34019           1178       0       3  
AS3491           28744       4488       364  
AS3549           1356       14       102  
AS37100           608       0       6  
AS37468           939       299       5  
AS3786           1       0       1  
AS40191           772       0       3  
AS41095           2252       0       6  
AS4230           804       170       3  
AS42525           712       255       2  
AS42708           732       132       2  
AS43531           121       100       2  
AS4637           5045       7758       378  
AS4657           2       0       2  
AS4755           19669       10632       342  
AS48362           1285       462       4  
AS4844           331       0       3  
AS50304           1086       211       5  
AS50629           1241       434       4  
AS51945           0       1       1  
AS52320           2343       164       14  
AS5511           214       0       5  
AS56665           1063       0       3  
AS577           1476       0       5  
AS58299           533       338       4  
AS58453           2021       0       5  
AS6057           814       72       4  
AS62240           1       0       1  
AS6327           1       0       1  
AS6453           35016       10659       336  
AS6461           11132       145       34  
AS6661           3       0       1  
AS6730           307       0       1  
AS6762           17388       4117       590  
AS6830           2028       750       16  
AS6939           16106       50366       137  
AS701           57       72       5  
AS7224           2589       0       4  
AS7473           43       0       2  
AS7575           805       176       6  
AS7707           12       0       1  
AS7738           874       0       3  
AS8218           3724       1517       11  
AS8220           9615       210       26  
AS8365           0       246       1  
AS8447           100       54       2  
AS8455           525       171       3  
AS8732           23       0       1  
AS8758           1695       579       5  
AS8943           54       22       1  
AS9002           13597       4649       34  
AS9044           184       0       1  
AS9299           2905       1185       369  
AS9304           258       0       3  
AS9318           13       0       1  
AS9498           253       0       204  
AS9957           8588       1475       450  
AS14586           360       0       19  
AS14618           47947       1468       538  
AS62785           965       0       532  
AS7224           249       0       211  
AS8987           4208       4412       442  
AS12350           668       0       2  
AS12637           538       0       2  
AS12779           2274       861       2  
AS1280           554       0       3  
AS12859           622       0       2  
AS13237           707       0       2  
AS1403           892       114       3  
AS14061           555       0       3  
AS14840           181       36       1  
AS14907           1079       169       4  
AS15435           525       169       2  
AS15547           2512       892       2  
AS15605           522       0       2  
AS16347           552       0       2  
AS17639           729       171       5  
AS18106           2028       495       5  
AS198290           552       0       2  
AS199283           595       200       1  
AS2018           517       161       2  
AS202032           1052       336       2  
AS207044           612       202       2  
AS20811           1239       0       2  
AS20912           522       167       2  
AS20932           622       221       2  
AS21232           530       169       2  
AS22652           993       138       3  
AS23106           1004       47       3  
AS24482           15387       2958       5  
AS25152           766       0       3  
AS25160           610       0       2  
AS25220           622       221       2  
AS25933           181       0       1  
AS262317           181       36       1  
AS262757           181       36       1  
AS263075           181       36       1  
AS263152           181       36       1  
AS263508           181       0       1  
AS263651           181       36       1  
AS264911           181       36       1  
AS267613           680       36       2  
AS28186           362       36       1  
AS28220           181       0       1  
AS28260           181       0       1  
AS28571           0       36       1  
AS28634           362       0       1  
AS28917           608       422       2  
AS29140           607       215       2  
AS29608           552       186       2  
AS29680           16       0       1  
AS31122           0       212       1  
AS31742           596       200       2  
AS327960           517       0       2  
AS327983           526       171       2  
AS328206           0       166       1  
AS328320           517       0       2  
AS328474           527       171       2  
AS34177           746       0       2  
AS34288           705       0       2  
AS35266           596       200       2  
AS35369           502       97       2  
AS37239           518       166       2  
AS37271           705       260       2  
AS37497           612       0       2  
AS37640           526       166       2  
AS37680           1255       0       2  
AS37697           517       0       2  
AS38001           956       0       2  
AS39122           762       287       2  
AS393950           766       0       3  
AS397143           929       131       3  
AS41497           522       0       2  
AS41722           0       164       1  
AS42473           733       36       2  
AS43100           550       0       1  
AS43578           531       0       2  
AS47147           2428       860       2  
AS47692           1824       645       2  
AS48526           608       215       2  
AS49605           1435       528       2  
AS49709           522       0       2  
AS50300           610       206       2  
AS50877           522       167       2  
AS51088           525       169       2  
AS51185           5377       0       5  
AS51873           530       169       2  
AS52720           181       36       1  
AS52863           181       36       1  
AS52873           655       247       2  
AS53067           0       36       1  
AS53070           181       36       1  
AS5392           522       0       2  
AS553           607       0       2  
AS56730           596       0       2  
AS57695           1294       402       2  
AS58308           1104       0       2  
AS59414           530       169       2  
AS59605           1416       351       3  
AS59689           552       0       2  
AS59891           530       169       2  
AS60501           635       0       2  
AS61595           181       36       1  
AS63956           417       133       2  
AS64050           458       0       2  
AS64271           181       0       1  
AS64463           530       169       2  
AS6667           732       0       2  
AS680           621       169       2  
AS6881           523       168       2  
AS7018           1636       0       5  
AS8222           608       0       2  
AS8283           525       169       2  
AS8426           777       220       2  
AS8607           596       0       2  
AS8896           602       203       2