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. > 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
