routing optimization for inter-domain traffic engineering under identifier network

论文 BGP 流量工程

Though many proposals share the same principles of problem – solving, the ID.Loc separation, they differ in how to achieve this goal. We observe that all the ID/Loc separation proposals fall into one of two categories:

• host-based,
• Network-based
  Network-based ID/Loc separation proposals split the edge networks from the transit core in the routing table size only grows with the number of Internet Service Providers (ISPs) which is much smaller and grows slower compared to that of edge networks.

强调的两点：

1. inbound
2. inter-domain

BGP: BGP is a path-vector routing protocol where a BGP router at the border of each AS announces to its BGP neighbor routers the prefixes it can reach.

BGP可以使用一些属性来影响Routing，从而改变流量。常见的标签有: 1. Local-Pref, AS path length, MED (Multi-Exit Discriminator) and communities. These attributes are used to manage the traffic. The Local-Pref gives a priority to the routes for a prefix. BGP chooses the route with the highest Local-Pref as the best route. Combining with the community attribute, an AS could set some prefixes advertised in a specific community.(固定前缀通告固定的社区) while neighbor ASes configure different communities with different Local-Pref values to inbound traffic. （这里不是很理解，利用local-pref做inbound） The ASes also can add the prefix to other communities, like NO_EXPORT community, to restraint the routing advertisement. AS path length is another technique to control the traffic. AS path length is another technique to control the traffic. If an AS tries to avoid the traffic from its neighbors passing through, it repeats its AS number multiple times in a AS path when the AS announces a prefix to its neighbors (a.k.a, AS Path prepending), since the longer AS path has lower priority to be selected.(AS长度越长，优先度越低) If an AS is connected with several routers to its neighboring AS, the MED allows an AS to signal the peers which point it prefers to import the traffic. BGP mixes the route selection in the control plane with the traffic forwarding in the data plane, which brings complicate and trivial configurations for the operators.
In current Internet, the most used method for adjusting inter-domain traffic is to advertise specific prefixes in more detailed granularity, or prefix de-aggregation. The principle of prefix de-aggregation is announce more specific prefixes to the preferred neighbors and less specific prefixes to the least preferred neighbors. As routing in the Internet is made on a longest prefix matching basis, a more specific prefix is always preferred to a less specific one.

评价：前面的背景部分写的还是很详细的。值得学习。问题阐述得很清楚。

后面的部分就是虚的了。没有实质内容：

1. routing identifier (RID)
2. Access Identifier (AID)
3. Connecting Identifier(CID)
4. Service Identifier (SID)

In order to elaborate the aspiration and details of our method for implementing inter-domain TE, we provide explanations of the proposed traffic engineering solutions in two specific circumstances, both of which consist of the comparison of the solution proposed in this chapter with traditional methods, also the advantage and deficiency(缺陷) of the proposed solution.