Hi Julian, You are right. But it's Client Routing for clients, right? A peer, however, can not attaches arbitrarily on the overlay. That is the exact difference between peers and clients in my previous e-mails. If what you mean is that peers can also been found by algrithm 2 when it lost its position in the overlay, the overlay would be messed up with disordered topology structure finally.
Br Lin -----Original Message----- From: ext jc [mailto:[email protected]] Sent: Saturday, October 24, 2009 8:08 AM To: [email protected] Cc: Xiao, Lin (NSN - CN/Beijing); [email protected]; [email protected] Subject: Re: [P2PSIP] New versions of RELOAD and sip draft In section 3.2.1. Client Routing contains two algorithms for Client routing. if you choose either of those algorithms then this won't be a problem. The first algorithm would forward through 500 around to 600(a direct connection). The second would use the destination list and form the route to 600 by storing information in the hash table. Finally, it is up to the Topology Plugin to ultimately handle this which Chord does so fine under this condition via it's own update (stabilization) procedures. Julian On Oct 23, 2009, at 3:47 PM, [email protected] wrote: > IMHO Lin Xiao has a quite valid point. If due changes of topology, > node 500 permanently loose its ability to interconnect with close ( in > DHT space) nodes, it has to be excluded from DHT ring or have to get a > new ID. > > Otherwise, it will became a permanent dead-end node for lookups for > targets in its immediate neighborhood that significantly degrades > speed of DHT lookup and ( under some conditions) can event result in > DHT space segmentation. > >> 500 can of course keep it's node id, regardless of whether 400 and/or >> 600 are there or not. Due to stabilization and by means of the >> successorcache the predecessor of 400 will notice the absence and >> bridge directly to 500 as well as 500 will skip 600 after a short >> time and go to 700 (in order to stay in the picture). Using notify >> the ring will close again. 400 and 600 may return whenever they want. >> >> Regards >> >> >> Xiao, Lin (NSN - CN/Beijing) schrieb: >>> Hi, >>> >>> Maybe I'm wrong, but I consider peers in RELOAD are structured with >>> a DHT algorithm, e.g., in Chord, peer with Node-ID 500 is connected >>> with peer 400 and 600. >>> >>> However, what will happen, if peer 500 totally lose both of the >>> connections due to mobility and NAT, but can set up new ones with >>> peer 100 and peer 300? IMHO, in order to keep the topology >>> structured, if this node still want to be a peer in the overlay it >>> should change its Node ID to, say 200, and rejoin the overlay to >>> enable itself still reachable with the DHT algorithm. >>> >>> If peers in a overlay can not be connected with a strict order, the >>> DHT algorithm for structured topology will not work anymore. >>> >>> >>> Br >>> Xiao, Lin >>> >>> -----Original Message----- >>> From: ext jc [mailto:[email protected]] >>> Sent: Thursday, October 22, 2009 12:41 AM >>> To: Xiao, Lin (NSN - CN/Beijing) >>> Cc: ext Cullen Jennings; P2PSIP WG >>> Subject: Re: [P2PSIP] New versions of RELOAD and sip draft >>> >>> The draft doesn't state that you MUST change you NodeID if you lose >>> overlay connectivity. In fact under your given condition you would >>> simply retain it and connect again as a Client when the network is >>> back up. >>> >>> Julian >>> >>> On Oct 21, 2009, at 3:59 AM, Xiao, Lin (NSN - CN/Beijing) wrote: >>> >>> >>>> Hi Cullen, >>>> >>>> Thanks for your reply. >>>> >>>> I agree that RELOAD have covered most of the functionalities of >>>> peers >>>> >>> >>> >>>> and clients. However, there is still a little different between >>>> clients and peers while connection is lost besides data replica. >>>> What >>>> I mean here is the Node ID. >>>> >>>> Because all the peers in the overlay are connected according to a >>>> strict overlay algorithm. The position of a peer in the overlay is >>>> decided by its Node ID. If a peer lost its position >>>> (disconnected) in >>>> the overlay because of moving and NAT, but still want to work as a >>>> peer, it must change its Node ID, which means it need do the >>>> enrollment again and rejoin the overlay. >>>> >>>> But, because a client can attach with an arbitrary peer. It is not >>>> necessary for a client to change its Node ID when it change its >>>> attaching peer. The most important thing here is that, this >>>> behavior make it possible for a client to keep session continuity >>>> while its attaching peer is switched. >>>> >>>> Considering to deploy RELOAD in reality, stable nodes are >>>> preferred to work as peers while mobile nodes can take the >>>> advantage of the client behavior mentioned above. Sessions can be >>>> kept with high mobility, as unique Node ID is maintained by >>>> clients. I'm not sure if RELOAD has considered this distinction of >>>> client, which help clients to be attached with the ovelay as long >>>> as it can build at least one connection to the overlay. >>>> >>>> Br >>>> Xiao, Lin >>>> >>>> >>>> >>>> -----Original Message----- >>>> From: ext Cullen Jennings [mailto:[email protected]] >>>> Sent: Friday, October 16, 2009 9:05 AM >>>> To: Xiao, Lin (NSN - CN/Beijing) >>>> Cc: P2PSIP WG >>>> Subject: Re: [P2PSIP] New versions of RELOAD and sip draft >>>> >>>> >>>> Thank you, few comments inline.... >>>> >>>> On Oct 10, 2009, at 2:20 AM, Xiao, Lin (NSN - CN/Beijing) wrote: >>>> >>>> >>>>> Hi Cullen, >>>>> >>>>> I've had a quick review of these two drafts, and still not quite >>>>> clear >>>>> >>>>> with some Client related issues. >>>>> >>>>> I know Client is not the first-class concept in RELOAD, but as it >>>>> has >>>>> >>> >>> >>>>> been involved in the RELOAD protocol, RELOAD should give full >>>>> support >>>>> >>> >>> >>>>> to client anyhow, right? >>>>> >>>>> In the terminology chapter of RELOAD Base draft, the connection >>>>> table >>>>> >>> >>> >>>>> is defined as: >>>>> "The set of peers to which a node is directly connected. This >>>>> includes nodes with which Attach handshakes have been done but >>>>> which >>>>> >>> >>> >>>>> have not sent any Updates." >>>>> although, the second sentence implies that clients are also >>>>> involved in, I still suggest to replace the "peers" in the first >>>>> sentence with >>>>> >>> >>> >>>>> "nodes" to make it more clear that both peers and clients can be >>>>> maintained in the table. >>>>> >>>> I agree. I changed this - thank you for the careful review to catch >>>> things like this. >>>> >>>> >>>>> In my opinions, connection setup and maintenance between client >>>>> and its connected peer (responsible peer or arbitrary peer) is a >>>>> key issue for client support in RELOAD. My question is: Does a >>>>> peer in RELOAD distinguish if the connection is to a peer or to a >>>>> client? >>>>> Because the reaction of the peer could be different when the >>>>> connection is lost. >>>>> >>>> Reload does distinguish at some level but what do you think a node >>>> needs to do differently when a connection is lost if the connection >>>> when to a peer or client. Clearly how data replication is handled >>>> and some of the finger table stuff is handled differently but I >>>> think that >>>> >>> >>> >>>> is covered in the draft. If you see something specific missing, let >>>> me >>>> >>> >>> >>>> know. >>>> >>>> >>>>> As a client could set up a connection only with an arbitrary peer. >>>>> Does >>>>> this peer distinguish such connection from those it is responsible >>>>> to? >>>>> >>>> I don't se the need to. >>>> >>>> >>>>> Should this peer inform the client's responsible peer about the >>>>> Destination List to the client? So that it can still be accessed >>>>> by other nodes. Or should the Destination List been stored with >>>>> some usage, say SIP Usage? >>>>> >>>> Yes, that is the approach to store destination lists where they are >>>> needed. >>>> >>>> >>>>> If so, the SIP usage must be extended to allow a Destination list >>>>> containing more than one Node IDs. >>>>> >>>> agree that it needs to allow storing multiple Node IDs but I think >>>> it already does that. >>>> >>>> >>>>> In current SIP >>>>> usage draft, the SipRegistration structure only allow one address >>>>> being stored in the Destination List, as: >>>>> " Destination destination_list<0..2^16-1>;" >>>>> >>>> The destination_list here is an array of Destinations so it allows >>>> between 0 and 65K entries in the array. I agree the syntax for >>>> specifying arrays might seem a bit weird but I think the structure >>>> is what you are pointing out we need to have. >>>> >>>> >>>>> It should be replaced by: "Destination destination_list >>>>> [dest_list_length];" >>>>> to enable a longer list stored by arbitrary connected clients. >>>>> >>>>> Anyway, IMHO, RELOAD should make sure to cover all situations a >>>>> client could meet or at least clearly distinguish issues of >>>>> clients, especially for arbitrary connected ones, which are left >>>>> to be solved by other drafts. Thanks. >>>>> >>>>> >>>>> Best Regards, >>>>> Xiao, Lin >>>>> >>>>> >>>>> -----Original Message----- >>>>> From: [email protected] [mailto:[email protected]] On >>>>> Behalf Of ext Cullen Jennings >>>>> Sent: Wednesday, October 07, 2009 1:53 AM >>>>> To: P2PSIP WG >>>>> Subject: [P2PSIP] New versions of RELOAD and sip draft >>>>> >>>>> >>>>> I just submitted >>>>> draft-ietf-p2psip-base-04 >>>>> and >>>>> draft-ietf-p2psip-sip-02 >>>>> >>>>> These contain technical changes but do not have a lot of editorial >>>>> changes. At some point we need to go and reorganize the documents >>>>> with editorial changes. >>>>> >>>>> Cullen <in my individual contributor role> >>>>> >>>>> _______________________________________________ >>>>> P2PSIP mailing list >>>>> [email protected] >>>>> https://www.ietf.org/mailman/listinfo/p2psip >>>>> >>>> _______________________________________________ >>>> P2PSIP mailing list >>>> [email protected] >>>> https://www.ietf.org/mailman/listinfo/p2psip >>>> >>> >>> _______________________________________________ >>> P2PSIP mailing list >>> [email protected] >>> https://www.ietf.org/mailman/listinfo/p2psip >>> >> _______________________________________________ >> P2PSIP mailing list >> [email protected] >> https://www.ietf.org/mailman/listinfo/p2psip > _______________________________________________ > P2PSIP mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/p2psip _______________________________________________ P2PSIP mailing list [email protected] https://www.ietf.org/mailman/listinfo/p2psip
