BGP Community String for Cable&Wireless AS1273

   April 7, 2007  Leave a comment

Attention

This BGP Community string information might be outdated. Please contact Cable&Wireless AS1273 to get more recent one. This BGP communites is ONLY for the customer who has BGP with Cable&Wireless AS1273. ipBalance.com is not maintaining this BGP Community string.

Instroduction

Cable & Wireless allows customers to control certain traffic flows off-net with the implementation of BGP community attribute values that prepend route/prefix paths with additional AS hops. These BGP community attribute values, which the customer applies, affects the way C&W peers choose the degree of preference of a given prefix/route, because the number of AS hops within the route-path has been lengthened.


Format

The format for the second component of customer route community number (after 1273:) is set at five digits. This fixed length allows regular expressions to be used in applying a defined number of prepends to a given route/prefix path. This format is 1273:3PPPN, where the fields are coded in the following way. (Note: The first digit of the second component is always "3" then followed by variables of the "PPP" and "N" variables which are defined in the following tables.)


Variables

The "PPP" variable cross references off-net connections of C&W, defined in the following tables. (Note, this will always be a three digit value.)


European peer PPP codes: (PPP values 100-200)

PPP Code Peer Name Peer AS Number
000 All Peers & upstreams  
200 MCI Europe AS702/AS12702
199 Global Crossing AS3549
198 SWIPNET AS1257
197 Tiscali AS3257
196 Telia AS1299
195 France Telecom AS5511
194 Swisscom AS3303
193 COLT AS8220
192 Eircom AS5466
191 Abovenet AS6461
190 DTAG AS3320
189 Arcor Mannesmann AS3209
188 AT&T EMEA AS2686
187 DFN AS680
186 Global Access AS13129
185 Globix AS4513
184 I-Primus AS5427
183 Mobilcom AS5430
182 Regionet AS8319
181 Telenor AS8210
180 Tesion AS15717
179 BT Ignite AS8472
178 Telefonica AS12956
177 Microsoft AS8086
176 Teleglobe AS6453
175 Reach AS4637
174 KPN Eurorings AS286
173 BBC AS2818
172 BT AS5400
171 Bredband AS8642
170 Yahoo Europe AS15635
169 MANDA AS8365
168 AUCS/Infonet AS3300
167 UPC Distribution Services AS6830
166 UTA.AT United Telekom Austria AS8437
165 Cablecom GmbH AS8404
164 Verio AS2914
163 LINX AS5459
162 Net Access AS8001
161 Telecom Italia Sparkle AS6762
160 Interroute AS8928
159 R-KOM Regensburger Telekommunikation AS12611
158 Cogent AS174
157 Schlund AS8560
156 Hurricane Electric AS6939
155 SongNetworks AS3246
154 PCCWBtN AS3491
153 Lambdanet AS13237
152 Versatel AS8881
151 Akamai Technologies AS20940
150 Google AS15169
149 Cable & Wireless UK AS5388
148 Sara AS1126
147 Giganews AS30094

 

 

American peer PPP codes: (PPP values 001-099)

PPP Code Peer Name Peer AS Number
099 TTSG Internet Services AS13945
098 Datapipe AS14492
097 ISPRIME AS23393
096 Primus Canada AS6407
094 HopOne AS14361
092 nLayer AS4436
091 Webair AS27257
090 Ezzi.net AS15149
089 Tellurian AS10848
088 DALnet AS31800
087 New York Internet AS11403
086 Microsoft AS8075
084 eBay AS11643
083 SBC Internet AS7132
082 RCN AS6079
081 Yahoo America AS10310
080 PCH AS42
079 PCH AS3856
078 Cox AS22733
077 Akamai Technologies AS12222
076 Rogers Cable AS812
075 Rackspace.com AS27357
074 MTS-Allstream Inc AS15290
073 Group Telecom AS6539
072 Adelphia communication AS19548
070 Shaw Cablesystems/Big Pipe Inc. AS6327
071 Broadwing AS6395
069 Thorn Communications AS12124
068 Limelight Networks AS22822
067 Stealth Communications AS8002
066 TMT Warner AS4323
065 TDS AS4181
064 Host.net AS13645
063 Terremark AS23148
062 Prolexic AS32787
061 Renesys AS64597
060 Mzima AS25973
059 Peer1 AS13768
058 Atlantech Online AS7784
057 Netifice Communications AS4565
056 NTELOS AS7795
055 Electric Lightwave AS5650
054 ESnet AS293
053 IIJ AS2497
052 TWGATE AS9505
051 China Telecom AS4134
050 Doubleclick AS6432
049 McLeod USA AS7228
048 Earthlink AS4355
047 Electronic Arts AS14891
046 Carpathiahost AS29748
045 Edge Networks AS19029
044 GNAP AS1784
043 Real Connect AS16559
042 BBC AS9156
041 Walmart AS17374
040 Comsat International AS7908
039 Cable Vision AS6128
038 Servercentral AS23352
037 WV Fiber AS19151
036 VOXEL AS29791
035 Choopa AS20473
034 US LEC AS1785
010 IDC Japan AS4694

Peering point PPP codes: (PPP values 970-989)

PPP Code Peering Point Name Peering Point Location
989 AMSIX Amsterdam, NL
988 DECIX Frankfurt, DE
987 INXS-HBG Hamburg, DE
986 INXS-MUC Munich, DE
985 LINX London, UK
984 PARIX Paris, FR
983 INEX Dublin, IE
975 NAP of the Americas Miami, FL, US
974 PAIX Palo Alto, CA, US
973 LAIIX Los Angeles, CA, US
972 Equinix Ashburn, VA, US
971 PAIX NY New York, NY, US
970 NYIIX New York, NY, US

Upstream PPP codes: (PPP values 990-998)

PPP Code Upstream Name Upstream AS number
998 Savvis Communications AS3561
996 Level 3 AS3356
995 Sprint AS1239

The "N" variable cross references the number of prepends, defined in the following table.
Allowable values of N:

Value Effect
0 Do not announce to selected peer
1 Prepend 1x to selected peer
2 Prepend 2x to selected peer
3 Prepend 3x to selected peer
9 Announce to this peer only (also announces to customers)

 

 

Examples

  • 1273:32000 – Do not announce to MCI Europe (AS702)
  • 1273:31752 – Prepend twice to Reach (AS4637)
  • 1273:39963 – Prepend three times to Level 3 Upstream connection (AS3356)
Please note that mixing a ‘prepend to IXP’ BGP community with a ‘prepend to specific peer’ BGP community may not have the intended effect. Prepending once to LINX and once to BT will lead to the route being prepended once to BT at LINX, whereas prepending an unequal number of times to an IXP and a peer at that IXP will lead to the sum of the prepends being added (e.g. prepending once to LINX and twice to BT will lead to three prepends being sent to BT at LINX). For this reason it is not recommended to mix specific and general prepend BGP communities on the same routes.

C&W Blackhole BGP Community Attribute Values (1273:666)

For customers that have a host or block under a DDoS, the affected host/block can be advertised to AS1273 with BGP community string 1273:666. This will cause all traffic to that host/block to be black-holed at the core of the AS1273 network.This action will trigger emails sent to the appropriate security and operations groups for notification purposes. After advertising the prefix with 1273:666, the customer may open a ticket to request further assistance with their Cable & Wireless management agency, or open a ticket via email to [email protected] Once the attack has been mitigated, the customer will be responsible for removing the prefix from being advertised. Cable & Wireless will not be held responsible for customers who errantly advertise prefixes with the blackhole community string.

C&W local preference alteration BGP communities

  • The local-preference hierarchy within C&W AS1273 is as follows
    Value Effect
    100 Customers (BGP and injected static)
    90 Backup customer connections
    80 Peers
    75 Transit/Upstream Providers
    70 Last resort customer connections
  • The following BGP communities can be sent to influence the local-preference of a customer route
    BGP Community String Effect
    1273:90 Sets local preference value within AS1273 to 90
    1273:80 Sets local preference value within AS1273 to 80
    1273:70 Sets local preference value within AS1273 to 70
    1273:no-export Prevents this route from being announce to
    any AS1273 EBGP peer
    1273:no-advertise Prevents this route from being announced to
    any AS1273 EBGP or IBGP peer

Applying BGP Community string with sample configuration

1. Get the latest BGP community string from your ISP/upstream provider or check www.ShowipBGP.com

2. Pick the best BGP community string for your traffic shaping plan (mainly incoming traffic).
Most of ISPs are providing community string with local preference and AS prepending
option. Cannot tell which one is better than the other. It will depend on your global traffic shaping plan.

3. Follow the below commands ( Cisco only )

The below Sample configuration will tag the 10.0.0.0/24 route with [ISP AS]:120 or [ISP AS]:3 and will not tag any other routes.

router#config t
router(config)#ip bgp-community new-format
router(config)#access-list 10 permit 10.0.0.0 0.0.0.255
router(config)#access-list 10 deny any

router(config)#route-map [to-ISP] permit 10
router(config-route-map)#match ip address 10
router(config-route-map)#set community [ISP AS]:120 <—- using Local Preference

or

router(config-route-map)#set community [ISP AS]:3 <——- using AS prepending
router(config-route-map)#route-map [to-ISP] permit 20
router(config-route-map)#exit

router(config)#router bgp [xxxx] <——————————- xxxx = customer’s ASN
router(config-router)#neighbor x.x.x.x send-community
router(config-router)#neighbor x.x.x.x route-map [to-ISP] out
router(config-router)#exit
router(config)#exit
router#copy running-config startup-config


4. And then, go to www.routeserver.org and pick one of route server on the map to see your announcement. If you are using AS prepending option, you will see your AS prepends on route servers. Sometime you might not see your route with particular ISP path.
In most of case it might not be any routing problem, just the route path was dropped at somewhere by BGP best path selection scheme. Try Oregon route server, if you can see your route. The Oregon route server is providing many possible and available paths between BGP speakers and neighbors.
If you don’t see your route on there? check other route servers and also check your
BGP configuration. You might need to contact your upstream provider to check what they are learning BGP route from you.

 


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