geneva, switzerland, 11 june 2012 switching and routing in future network john grant nine tiles...
TRANSCRIPT
Geneva, Switzerland, 11 June 2012
Switching and routingin Future Network
John GrantNine Tiles
[email protected]/FN-standardisation.html
Joint ITU-T SG 13 and ISO/JTC1/SC 6 Workshop on
“Future Networks Standardization”
(Geneva, Switzerland, 11 June 2012)
Geneva, Switzerland, 11 June 2012 2
the one part of the stack that's universal
Network layer
routing
encapsulation
physical layers
applications
transport protocols
users
Geneva, Switzerland, 11 June 2012
like ISO 668, 1161, ...
Geneva, Switzerland, 11 June 2012 4
Two kinds of data
static dynamic
contentfiles, web pages, etc
audio, video, voice
context IT AV; real world
traffic bursty regular
service best effort needs QoS
IP designed for?
yes no
Geneva, Switzerland, 11 June 2012
Two kinds of service
Synchronousappropriate for dynamic dataone-to-manypackets sent at regular intervalsQoS guarantees (if supported by lower layers)
Asynchronousappropriate for static dataone-to-one or many-to-onebest-effort service
(not 1, not 4)
Geneva, Switzerland, 11 June 2012 6
Connection-oriented paradigm
Required for synchronousneeded for QoS etc negotiation
Useful for both kindsoffers facilities such as per-call billing
Fits many current protocolsTCPSIP“sockets” API
Geneva, Switzerland, 11 June 2012 7
Connection-oriented paradigm
Provides separation between:global addressing (in set-up messages)local routing (in packets)
Enables new routing technologiesno “world launch day” needed
Connection-oriented ≠ TDMthough FN supports use of TDM and WDM circuits
Geneva, Switzerland, 11 June 2012 8
Connection-oriented paradigm
“Link” between network elements may be:
point-to-point connectionshared media (e.g. WiFi, LTE)legacy network, including connectionless
Provides migration pathon legacy network, only edge / gateway devices need to implement FN
Geneva, Switzerland, 11 June 2012
Switch structure
controller (computer)
routing table
buffermemory
inputs outputs
control packets etc
logiclogiclogiclogic
scheduling
Geneva, Switzerland, 11 June 2012 10
Addressing
Access to a service by name in IPuse DNS, SIP, etc, to find IP addressIP address is then used for packet routing
switches use ARP to find lower-layer address
problems with mobility etcdocumented in TR29181
Geneva, Switzerland, 11 June 2012 11
Addressing
Access to a service by name in FNput service name in signalling messagereply includes a “handle” for the routehandle format depends on the link technology for the first hopeach network element only needs to know the local part of the routererouting, handover, etc are transparent
Geneva, Switzerland, 11 June 2012 12
Fast set-up for asynchronous
HTTP typically uses many short TCP sessions
after the first, the addresses are already in the routing table
for popular web sites, destination is there even for the first
return route can be cached as the SYN packet is forwarded
Geneva, Switzerland, 11 June 2012 13
Fast set-up for asynchronous
FN has an equivalent for connection-oriented
connection to server is many-to-onereturn route set up by switching fabric
does not involve controller software
described in 8.2 of 29181-3
Geneva, Switzerland, 11 June 2012 14
Finding a route
Application sends request to local controller on signalling channel
includes address (or other identification) of target
target is the equipment, not its interfacemay also be a service or some content
also includes a globally-unique “call identifier”
Geneva, Switzerland, 11 June 2012 15
Finding a route
Multiple addressing schemesmust support legacy schemes, e.g. IPv4, IPv6must also support URLs etc
must allow new schemes to be addeddecoupling global addressing from local routing means no change is needed to lower-layer switching logic
unlike the change from IPv4 to IPv6
Geneva, Switzerland, 11 June 2012 16
Finding a route
Controller in each switch decides the next hop
topology discovery depends on the address schemein sub-networks, may simply flood the request to all neighbours
loops easy to detectnot scalable to large networks
Geneva, Switzerland, 11 June 2012 17
Finding a route
Controller checks required capacity is available
provided the switching technology supports it
Labelling of packets depends on link technology
route may pass over several different technologies
Geneva, Switzerland, 11 June 2012 18
Control / signalling protocol
Tag-length-value formatlike Q.931, Q.2931; unlike SIPsuitable for small embedded processors
no character string interpretation requiredappropriate for Internet of Things
easy to skip unrecognized / uninteresting items
some for network, some for remote application
Could be based on IEC 62379-5-2
Geneva, Switzerland, 11 June 2012 19
Next steps
Find a name without “future” in itsoon (2015?) it’ll be in the present
Standardize signalling messagesincluding route-finding protocols
Standardize new lower layer(s)QoS for synchronous flowslow overhead per packetall capacity not used by synchronous flows available for asynchronous