NetworkTalk & BGP

A.2.a) Type, size and marging tuning connectivity questions on Upsteam/transit providers

A.2.a) Type, size and marging tuning connectivity questions on the Upsteam/transit providers.

  1. Most importantly, before thinking a traffic engineering case, it is recommended to be aware of the following information regarding the transit/upstream providers, that the customer ISP wish to be linked with:
    1. The type? Is the ISP a Tier1, Tier2 or Tier 3 size?
    2. The network engineering rules proposed to the customers?
      Does the ISP allow its customer to use BGP community rules?
    3. In the case, that the ISP allows the customer to use community rules, which attribute regarding the network advertised by the customers, can be modified within the ISP network?
      LocalPref, Prepend, suppression, country communities …
    4. How does the ISP tag the routes received by its peer?
      If a prefix is advertised from the customer to several ISPs, how does an ISP announce the customers prefixes to its peers and how does it tag it (if these same prefixes are received from another peer)?
  2. After reviewing these points, we can have a better picture of the limitation and the margin of tuning about our traffic engineering design. It is important to note:
    1. The customer can easily define a policy about how to send outgoing IP-packets on the correct link.
      Nevertheless, it is much harder to influence the neighboring AS, on how to direct the IP-packets into the customer network.
    2. In other words, traffic engineering about controlling your ingress/inbound/download traffic is more difficult than controlling your egress/outbound/upload traffic.
      Control of ingress/inbound/download requires a good knowledge of your ISPs rules and peering agreement with others ISPs.

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