Cable & Wireless allows customers to control certain traffic flows off-net with the implementation of community attribute values that prepend route/prefix paths with additional AS hops. These 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.

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.)

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)

• 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' community with a 'prepend to specific peer' 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 communities on the same routes.

For customers that have a host or block under a DDoS, the affected host/block can be advertised to AS1273 with 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 trouble@eu.cw.net 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.