Predictive multicast cache
View Patent ↗A method is provided for distributing multicast channels from a multicast/predictive multicast cache located in at least one selected network device of a multicast network. The network device upon receiving a channel request from an end-user transmits the requested channel from the multicast cache if the requested channel is available in the multicast cache. Else, the network device requests the multicast source for the requested channel along with a group of one or more multicast channels centered at the requested channel. The network device transmits only the requested channel and other channels are cached in the multicast cache on the network device. Upon receiving a request for removing a channel the network device caches the channel for a prescribed duration before evicting the channel.
1. A method of multicast channel distribution comprising the steps of:
at least one end-user sending a channel request to at least one network device, wherein upon receiving the channel request, the at least one network device;
verifying, if the requested channel is available in a multicast cache on the network device, and if the requested channel is not replicated at least once for another end-user; and
if the requested channel is available in the multicast cache then
provisioning the requested channel to the at least one end-user from the multicast cache; else
forwarding the channel request and a predetermined number of additional requests for pre-fetching the predetermined number of additional channels to the multicast source;
receiving the requested channel along with the one or more additional channels from the multicast source,
caching the predetermined number of additional channels in the multicast cache, and
provisioning only the requested channel to the at least one end-user, so as to reduce the penalty;
wherein the requested channel and the cached predetermined number of additional channels comprise a channel window having a center at the requested channel.
2. The method of claim 1 , wherein the multicast cache is a predictive multicast cache having a multicast cache size of a pre-determined number of channels.
3. The method of claim 1 , wherein upon receiving a new channel request in a channel window other than the current channel window, the network device sliding the channel window thereby, centering the new channel window preferably at the newly requested channel.
4. The method of claim 1 , wherein the network device reducing one or more channel window such that, the total number of the cached channels in the channel window does not exceed the multicast cache size.
5. The method of claim 2 , wherein the network device allotting a respective channel window to each end-user.
6. The method of claim 1 , wherein the multicast cache is flushed periodically such that the cache size does not exceed the multicast cache size.
7. The method of claim 2 , wherein the network device evicts one or more cached channels such that, the total number of cached channels does not exceed the multicast cache size.
8. The method of claim 5 , wherein the network device reducing one or more of the channel windows such that, a combined cache size of the channel windows is less than, or equal to the multicast cache size.
9. The method of claim 5 , wherein the respective channel windows have substantially the same window size.
10. The method of claim 5 , wherein the respective channel windows of one or more end-users substantially overlap.
11. The method of claim 6 , wherein a method for periodically flushing the multicast cache is the one selected from a Least Recent Uses (LRU) algorithm, attaching a timer to each cached channel, and a combination thereof.
12. The method of claim 10 , wherein two or more overlapping channel windows are merged.
13. The method of claim 11 , wherein the network device maintains the timers attached with each cached channel, such that each cached channel is periodically flushed in a prescribed manner.
14. The method of claim 12 , wherein the network device reducing one or more of the channel windows after merging overlapping channel windows such that, a combined cache size of the channel windows is less than, or equal to the multicast cache size.
15. A method of removing a multicast channel comprising the steps of:
at least one end-user sending a ‘leave channel’ request to at least one network device, wherein upon receiving the request, the at least one network device;
stopping the transmission of the requested channel to the end-user;
caching the requested channel in a multicast cache after stopping the transmission to the end user for a prescribed duration;
verifying if the requested channel is not replicated at least once for another end-user after stopping the transmission to the end user; and
evicting the requested channel from the multicast cache after the prescribed duration, so as to reduce the penalty.
16. The method of claim 15 , wherein the network device evicting channels by operating electronic timers attached to the cached channel.