Date: March 11, 2000
Author: Ronald Wolak

Subject: Reply 1 to William Schmidt's: Other Business Uses

Reply 1 to William Schmidt's: Other Business Uses

Related to the discussion of the use of IP multicasts to broadcast video-based multimedia applications are performance issues when the Internet is used as the carrier (Xue, Ammar, & Paul, 1999, March-April). Currently, the lack of quality of service (QOS) support on the Internet makes the transmission of real-time multimedia traffic a challenge. Other issues include the heterogeneity of the Internet's transmission systems. These diverse systems make it difficult for multiple receivers of the same video stream to agree on acceptable traffic characteristics. New layered video multicast protocols are being developed to address this problem. These include receiver-driven layered multicast (RLM) and layered video multicast with retransmissions (LVMR).

Another proposed solution to the problem is a loss recovery scheme called active reliable multicast (ARM) (Lehman, Garland, & Tennenhouse, 1998). ARM networks would use routers in the multicast tree that take an active role in recovering data losses. In addition, soft-state storage is utilized by ARM networks to improve performance. ARM is a novel and practical solution to the lack of QOS on the Internet because it does not require all nodes to be active. Significant results are achieved even when less than half the routers within the multicast tree perform ARM processing.

The widespread deployment of video-based multimedia applications over the Internet is dependent upon successful implementation of software and hardware based solutions such as those described above.

References

Lehman, L., Garland, S., & Tennenhouse, D. (1998). Active reliable multicast. Seventeenth Annual Joint Conference of the IEEE Computer and Communications Societies, IEEE, pp. 581-589.

Xue, L., Ammar, M., & Paul, S. (1999, March-April). Video multicast over the Internet. IEEE Network, 13(2), 46-60.