XID protocol is compared with alternative image distribution schemes for a data center network such as BT, VDN, HL, and XID-BF.
The chunk signaling overhead of 20byte long SHA-1 hashes can grow up to 5MB for VDN, HL, XID, and XID-BF protocols.
A downside of this protocol is that it incurs larger overhead compared to XID protocol, since a hash value has to be associated one-to-one with a particular chunk.
Cross-image sharing leads to good performance for the rest of the protocols with XID and XID-BF protocols showing the best results.
The percentage of intra, inter, and server cases for XID protocol is 46:34:20, while the numbers are 44:37:19 for XID-BF protocol.
7, XID-BF is able to complete its download of CentOS 5.8 image faster than any others in about 18 seconds, which is closely followed by 22 seconds of XID protocol.
In contrast, a cluster of chunks can be collectively indicated by a single hash for XID protocols.
XID and XID-BF do much better to obtain 2.2 and 2.6 chunks at the expense of a single hash.
The protocol achieves savings in terms of the bit length of individual hashes being transferred, while our XID scheme saves hash overhead at the granularity of a group of hashes.