The loss path multiplicity problem in multicast congestion control
The loss path multiplicity problem in multicast congestion control
复制标题
组播拥塞控制中的丢失路径重数问题
DOI：
10.1109/infcom.1999.751474
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
J. Kurose
中科院分区：
文献类型：
--
作者：
S. Bhattacharyya;D. Towsley;J. Kurose
基于源的组播拥塞控制算法的一个重要问题是丢失路径多重性（loss path multiplicity， LPM）问题，因为传输的数据包可能在组播树的一个或多个端到端路径上丢失。因此，如果组播源的传输速率是根据接收方的丢失指示来调节的，那么随着丢失路径数量的增加，传输速率可能会完全受限。在本文中，我们分析了一类加性增加乘性减少拥塞控制算法，并表明，除非仔细注意LPM问题，否则组播会话的平均会话带宽可能会随着组播组规模的增加而急剧减少。这使得在单播和多播会话之间以最大最小公平的方式共享带宽变得不可能。然而，如果每个组播会话根据其组播树中最拥塞的端到端路径调节其速率，则可以实现最大最小公平性。我们提出了一种理想化的协议，用于在不断变化的网络条件下跟踪最拥塞的路径，并使用仿真来说明跟踪最拥塞的路径确实是一种很有前途的方法。
An important concern for source-based multicast congestion control algorithms is the loss path multiplicity (LPM) problem that arises because a transmitted packet can be lost on one or more of the many end-to-end paths in a multicast tree. Consequently, if a multicast source's transmission rate is regulated according to loss indications from receivers, the rate may be completely throttled as the number of loss paths increases. In this paper, we analyze a family of additive increase multiplicative decrease congestion control algorithms and show that, unless careful attention is paid to the LPM problem, the average session bandwidth of a multicast session may be reduced drastically as the size of the multicast group increases. This makes it impossible to share bandwidth in a max-min fair manner among unicast and multicast sessions. We show that max-min fairness can be achieved however if every multicast session regulates its rate according to the most congested end-to-end path in its multicast tree. We present an idealized protocol for tracking the most congested path under changing network conditions, and use simulations to illustrate that tracking the most congested path is indeed a promising approach.