> On Sep 3, 2020, at 8:32 PM, Bruce Fields <bfields@xxxxxxxxxxxx> wrote: > > On Thu, Sep 03, 2020 at 07:48:19PM -0400, Chuck Lever wrote: >> Hi Bruce- >> >>> On Sep 3, 2020, at 5:52 PM, J. Bruce Fields <bfields@xxxxxxxxxxxx> wrote: >>> >>> I've been thinking about what might be required for NFS to run over >>> QUIC. >>> >>> Also cc'ing Steve French in case he's thought about this for CIFS/SMB. >>> >>> I don't have real plans. For Linux, I don't even know if there's a >>> kernel QUIC implementation planned yet. >>> >>> QUIC uses TLS so we'd probably steal some stuff from the NFS/TLS draft: >>> >>> https://datatracker.ietf.org/doc/draft-cel-nfsv4-rpc-tls/ >> >> The link to the latest version of that document is >> >> https://datatracker.ietf.org/doc/draft-ietf-nfsv4-rpc-tls/ >> >>> For example, section 4.3, which explains how to authenticate on top of >>> an already-encrypted session, should also apply to QUIC. >> >> Most of the document's content will be re-used for defining >> RPC-over-QUIC, for example the ALPN defined in Section 8.2. >> Lars Eggert, a chair of the QUIC WG, has been helping guide >> the RPC-over-TLS effort with an eye towards using QUIC for >> RPC when QUIC becomes more mature. >> >> I thought the plan was to write a specification of RPC-over- >> QUIC as a new RPC transport type with a netid and uaddr along >> with a definition of the transport semantics (a la TI-RPC). >> The document would need to explain record marking, peer >> authentication, how to use multi-path and multi-stream support, >> and so on. >> >> Making NFS work on that transport should then be straightforward >> enough that perhaps additional standards work wouldn't be >> necessary. > > Oh, OK, good. Sounds like you're way ahead of me, then, I didn't know > there was a plan. That's all there is for the moment! :-) > --b. > >>> QUIC runs over UDP, so I think all that would be required to negotiate >>> support would be to attempt a QUIC connection to port 2049. >>> >>> The "Transport Layers" section in the NFS RFCs: >>> >>> https://tools.ietf.org/html/rfc5661#section-2.9 >>> >>> requires transports support reliable and in-order transmission, forbids >>> clients from retrying a request unless a connection is lost, and forbids >>> servers from dropping a request without closing a connection. I'm still >>> vague on how those requirements interact with QUIC's connection >>> management and 0-RTT reconnection. >>> >>> https://www.ietf.org/id/draft-ietf-quic-applicability-07.txt looks >>> useful, as a guide for applications running over QUIC. It warns that >>> connections can time out fairly quickly. For timely callbacks over NFS >>> sessions, that means we need the client to ping the server regularly. >>> Sounds like that's what they do for HTTP/QUIC to make server push >>> notifications work: >>> >>> https://tools.ietf.org/html/draft-ietf-quic-http-09#section-5 >>> >>> HTTP clients are expected to use QUIC PING frames to keep >>> connections open. Servers SHOULD NOT use PING frames to keep a >>> connection open. A client SHOULD NOT use PING frames for this >>> purpose unless there are responses outstanding for requests or >>> server pushes. >>> >>> QUIC allows multiple streams per connection--I wonder how we might use >>> that. RFC 5661 justifies the requirement for an ordered transport with: >>> >>> Ordered delivery simplifies detection of transmit errors, and >>> simplifies the sending of arbitrary sized requests and responses >>> via the record marking protocol. >>> >>> So as long as we don't try to split a single RPC among streams, I think >>> we're OK. Would a stream per session slot be reasonable? I'm not sure >>> what the cost of a stream is. >>> >>> Do we need to add a new universal address type so the protocol can >>> specify QUIC endpoints when necessary? (For server-to-server-copy, pnfs >>> file layouts, fs_locations, etc.) All QUIC needs is an IP address and >>> maybe a port, so maybe the existing UDP/TCP addresses are enough? >> >> -- >> Chuck Lever >> chucklever@xxxxxxxxx -- Chuck Lever chucklever@xxxxxxxxx
