Provider: Cable & Wireless Plc. (AS1273). Source: http://www.as1273.net object /. Provider page
The new implementation allows for a 5 digit string, following the “1273:” notation. Each bit/digit has a pertinent value and meaning represented in the following tables (1273:xxxxx). This was facilitated to provide the following routing information to customers receiving a routing table from C&W via eBGP routing.
Identification of route source by
“S” refers to ‘source’ of the route:
Example:
1273:1xxxx customer route 1273:2xxxx peer route 1273:3xxxx upstream route
1273:11xxx customer, North America 1273:24xxx peer, Australia
1273:11840 customer, North America, United States 1273:22000 Peer, Europe, Italy 1273:31000 Upstream provider, North America, United States
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 "PPP" variable cross references off-net connections of C&W, defined in the following tables. (Note, this will always be a three digit value.)
Allowable values of N:
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.
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