When Louis Touton and I wrote the escrow language in 2001 we envisioned registries doing dumps to physical media, hence the compression language.
The current draft language bans physical media, which is a kind of error, since write-once media and even some incremental dump losses still allows the reconstruction of a registry sufficient to meet the reasonable business standard, and can't be attacked by AS prepending and other attacks. However, given the no-physical-media proposed rule, just what is the point of the compression langague?
A registry with very large full or incremental dumps is likely to be served by GigaE connectivity, and the escrow dump had better be adequately bandwidth provisioned to sink the data flows, so ... what's the point with compression?
Thanks in advance, Eric