SUA Tutorial 03

Information and Communication NetworksSUA tutorial SCCP User Adaptation Layer tutorial Authors: Lode Coene Gery Verwimp © Siemens Atea Information and Communication Networks SCCP user adaptation layer(SUA) Application (+TCAP) - replaces the functionality of SCCP and M3UA over SCTP in an IP network - required for 3G mobile networks (from Release 5 onwards) -> Nokia, Ericsson - also applicable for IN (TCAP over IP) - runs on top of SCTP - standardization in stable mode - Transport Independent SCCP is a direct competitor (ITU-T) ISUP, SCCP classic SS7 SUA adapts SCCP Users to SCTP M3UA adapts MTP 3 User Parts to SCTP SCTP IP 2 SUA tutorial 04.01.2011 © Siemens Atea Information and Communication Networks SUA status in IETF & outside ‡ new draft 09 (November) ‡ Applicability of SUA:  Mobility Management in Wireless 3G systems (MAP)  IN services for fixed and wireless systems (INAP.2011 © Siemens Atea . CAP) in circuit switched and VOIP systems  SMS offloading  Iu interface (UTRAN/GERAN: between radio access and core network)  Corporate GSM  Signaling Gateways  Signaling Relays 3 SUA tutorial 04.01. 01.Information and Communication Networks Basic SUA Network architecture gt· B1 A1 gt gt gt·· gt· relayNodeEntitySet 4 D1 gt··· E1 D2 C1 B2 SUA tutorial 04.2011 © Siemens Atea . HLR.2011 © Siemens Atea . SMSC«) independent from the underlying technology used (TDM. ATM«)   PSTN ± IP interworking all IP network ‡ How should Global Title Translation be done  Distributed : use of local GT databases  Central : remote database accessed via LDAP«  Hierarchical : remote database accessed via DNS« 5 SUA tutorial 04.01. IP.Information and Communication Networks SUA network architectures ‡ Basic SCCP/SUA architecture: to have end-to-end communication between different entities (SGSN. 01.Information and Communication Networks PSTN ± IP interworking Global SS7 overlay network SS7 SS7 SS7 SS7 SS7 over TDM SS7 over IP en SS7 SS7 SS7 PSTN / ISDN Switch Switch Switch SS7 SS7 m MSC SCPLNP Circuit switched POTS/ISDN Mobile IN IP/MPLS Core Network Circuit switched network 6 Next Generation Network 04.2011 SUA tutorial © Siemens Atea . SUA MTP SCTP 1-3 IP TCAP SUA SCTP IP 7 SUA tutorial 04.2011 © Siemens Atea .01.Information and Communication Networks PSTN ± IP Protocol Interworking en HLR or SCP within an IP network PSTN MSC (or SSP) Signalling Gateway IP-based Network HLR (or SCP) MAP/INAP MAP/INAP TCAP SCCP MTP 1-3 SCCP Interw. .2011 © Siemens Atea ... . SUA SCTP IP AAL5/Ether SRP : SUA SCTP IP AAL5/Ether SUA SCTP IP AAL5/Ether 8 SUA tutorial 04. SRP HLR .. Association: SMSC Protocol Stack MAP. RANAP..01. SRP .. IN.Information and Communication Networks Network border SGSN SRP . . 2011 © Siemens Atea .01.Information and Communication Networks SUA implementation architecture ‡ SUA runs as a User plane implementation in Linux ‡ makes use of the Siemens SCTP implementation (www.sctp.de ) ‡ uses the SCTP ³function callback´ mechanism 9 SUA tutorial 04. Information and Communication Networks SUA : supported features Routing Options for Connectionless Services routed on IP address & SSN     Supply the origination an destination IP address Supply the application Subsystem Number(SSN) Message will be routed onto the correct SCTP association towards the destination IP address (= direct associated routing) It might turn out that there is no direct SCTP association between the local SUA node and the destination SUA node. but different address syntax (32/128 versus 14/24 bit) Supply the origination (= calling party) and destination (= called party) Global Title (or Hostname in case of extended AMF) address Supply the optional application SSN Message will be routed onto the correct SCTP association towards the destination IP address derived via Global Title Translation (GTT). SUA tutorial 04.01. If no direct association exists .2011 routed on Pointcode & SSN:      10 routed on GT & SSN © Siemens Atea . then SUA will route via intermediate SUA nodes based on the IP address. then SUA will use quasi-associated routing (wow route via intermediate SUA nodes based on IP address) same as IP address & SSN. Information and Communication Networks SUA : supported features Connection Oriented Services ‡ Connection oriented service   only protocol class 2 association of connection sections is not supported ‡ Same routing options for CORE (COnnection REquest) as for the connectionless messages. 11 SUA tutorial 04. ‡ Routing for subsequent msgs of a SUA connection is done using the stored association Id in the SCOC TCB.01. thus routing based on IP address or GT is not done.2011 © Siemens Atea . if possible.2011 © Siemens Atea . The way in which traffic is shared over the ASP of a AS is implementation dependent. ASP management is identical for all UAs     ‡ comparison with M3UA 12 SUA tutorial 04.) within the AS. However traffic that needs the same server (such as TCAP msgs belonging to the same transaction) must be sent to the same ASP. The ASP within the Application server can be processing traffic or can be in standby.Information and Communication Networks SUA : supported features ASP Management ‡ reachability of endnodes/ application servers : ASP management    ASP : application server process AS : application server: An Application Server contain at least one ASP.01. A more global solution will be provided using Rserpool technology. An ASP can belong to different Application Servers If a ASP would fail then internal mechanisms have to provide for the transfer of state (example state of TCAP/application transaction. 01.g. Use is still not very clear. but is also extendable to an all-IP infrastructure (single node = combined SG and AS) Still requires the use of a pointcode overlay of the all IP network SS7 management gives the impression that the SG+ASP¶s is a SS7 node(end/relay) towards the SS7 network. Interop seems very doubtful here. especially if this is extended to the peer-topeer IPSP . e.IPSP case (double-ended registration). Should be treated as extremely dangerous. ‡ Error and notify msg   ‡ Dynamic registration of ASP to a SG 13 SUA tutorial 04. their effect on ASPSM/ASPTM procedures.Information and Communication Networks SUA : supported features ASP Management ‡ Difference between SS7 management and ASP management        ASP management only deals with adjacent nodes SS7 management indicates statuses from non-adjacent nodes or routes (STP) Indicates to a ASP to start/stop sending traffic to the SG for a specified DPC and SSN Also congestion levels may be exchanged with the ASP SS7 management is in principle only used for interworking between a PSTN and a IP network.2011 © Siemens Atea . 01.2011 © Siemens Atea .Information and Communication Networks IP network ASP1 SPC2 SSb AS SG SPC1 ASP2 SPC3 SSb 14 SS7 network or SG + AS(P) SCMG SPCx SSz SSy SUA tutorial 04. Information and Communication Networks Global title aspects IP network operator 2 SUA uses a digit pattern which is translated from node to node until the final destination is reached -> Global title (e.01.2011 SUA tutorial © Siemens Atea . MSISDN number : CC + NDC + SN) IP network Operator 1 15 IP network operator 3 04.g. . . enforcement of roaming agreements. Expands the addressing capabilities       E164 to E212 E164 to hostname Hostname to hostname hostname to E164 IPv4 . The relay point is the box and it is explicitly visible towards other SUA relay points or SUA endpoints in both the normal internet and the NAT.01. If relay point is used for transitioning into the NAT then IPSEC can be used.Information and Communication Networks SUA : supported features Relay service : provide GTT (AMF ?) service Useful for NAT crossing : no unknown NAT middlebox needed.2011 © Siemens Atea .IPv6 network or NAT border crossing Pseudo end-to-end :network architecture hiding Allow for loadsharing across a pool of relay points (using Rserpool or own SUA built in protocol) ‡ 16 SUA tutorial 04.. Can be used as a firewall for SUA traffic : example removal of SMS spam traffic. 2011 © Siemens Atea .01.DNS root DNS Information and Communication Networks Use of ENUM in SUA DNS X gt· DNS DNS A DNS B B1 A1 gt gt gt·· gt· relayNodeEntitySet 17 D1 gt··· E1 D2 C1 B2 SUA tutorial 04. 01. something that is very BAD for reliability and contrary to any SS7 network design up till now(SS7 favors greatly a peer-to-peer network design and SS7-over-IP should benefit from that) A name in the DNS can return many IP addresses and not all those address may belong to the same. That would mean that SUA should not be caching the DNS info but always have the up-to-date info of all its adjacent SUA peers. which would lead to a SUA hierarchical network design. but raises other issues) the response time from the DNS is unpredictable due to its hierarchical architecture. node -> DNS is sometimes used for loadbalancing across multiple nodes and it is impossible to make a difference between a truly multihomed (SUA)node and a a bunch of replicated (SUA) nodes(with no multihoming attached to each single node naturally) (Except if you start finding it out for yourself by setting up association with each of the addresses)   18 SUA tutorial 04. Would produce a WWW(world wide Wait) effect on SS7 traffic Using the Time-to-live(TTL) from the DNS records is quite useless as SUA would have a direct connection with the remote SUA node(and thus know far much better if the remote side is active or not).Information and Communication Networks SUA: supported features Building the GT tree of the relaying service via DNS(ENUM) ‡ Normal way of using DNS is to invoke GetHostname for every message that passes: More negative points than positive    would create a DNS message flood in the DNS system as all connectionless msgs use E164/E212 numbers(if numbers gets cached. this problem may be reduced . Is less flexible than the standard Global Title Translation function: a DNS name when distributed in DNS will always map to the same set of IP addresses (= SUA nodes) independent from the place where the resolving is requested.2011 © Siemens Atea . release. portnumber ‡ Difference between end and relay point.   static associations dynamic associations (pure end-to-end) ‡ ASP issues -> relation to Rserpool ‡ TESTIP: Basic tester for testing the capabilities of SUA ‡ Not compatible (yet) with the EWSD based TEST User part 19 SUA tutorial 04.2011 © Siemens Atea .01. mapping (distribute traffic over different associations according to addressing info).Information and Communication Networks Use of SUA with SCTP ‡ Association setup. SSN. .e. SUA does NOT require SS7 pointcodes (administrative) in principle. I. the Routing Contexts can be more fine-tuned. Can use extended addressing capabilities which are not included in SCCP (use of IP address and of hostname/DNS names) yet..01. Management should be simpler as only one layer (SUA ASP management) has to be administered versus 2 (M3UA ASP management + SCCP management).Information and Communication Networks Comparison with other stacks (1) ‡ SUA <-> SCCP+M3UA     SUA has better knowledge of the underlying network than SCCP on top of M3UA. but the traditional SCCP users may still require PC or SSN status indications . 20 SUA tutorial 04.2011 © Siemens Atea . if run directly over SCTP.01. via the appropriate STC.Information and Communication Networks Comparison with other stacks (2) ‡ SUA <-> transport independent SCCP    Just as SUA.2011 © Siemens Atea . TI-SCCP can be run over M3UA as well. TI-SCCP doesn¶t have extended addressing capabilities yet. TI-SCCP would lack the MTP3 transfer functionality and point code overlay to support traditional management procedures. This may change but is up to TI-SCCP standardisation (example IP address/hostname/DNS name) 21 SUA tutorial 04. 01. but has extended features ‡ SUA supports the basic IP addressing architecture and DNS naming 22 SUA tutorial 04.2011 © Siemens Atea . where segmenting/reassembly can be left to SCTP « because it can be fine-tuned to SCCP applications this advantage depends of course on applications using the extended addressing capabilities ‡ SUA can transport bigger messages for all its applications    ‡ SUA is less complex than M3UA+SCCP.Information and Communication Networks SUA applicability ‡ SUA can transport bigger SMS messages (nr of char >> 160)  however. but requires adaptations to MAP protocol and raises interworking issues particularly useful in all-IP. this would also be true for traditional SCCP and TI-SCCP. Hughes Software Systems(HSS).01. 23 SUA tutorial 04. Herentals Belgium ‡ 5 Companies attended: Performance Technologies(PTI).Information and Communication Networks 1st SUA bakeoff 5 ± 9 November 2001 ‡ Done at Siemens atea.2011 © Siemens Atea . Cisco and Siemens ‡ No big problems detected with spec ‡ Most implementations only supported Connectionless and were acting as Signalling gateway ‡ Connection-oriented worked also -> to be used in 3GPP?? ‡ Basic SUA Management worked. Radisys. phone: +32-14-253424 Implementation is open source . whatever.be. phone: +32-14-252081 Gery Verwimp : Email: Gery.2011 © Siemens Atea .Information and Communication Networks Conclusion Bug reports.sctp. Source is to be released under the GPL on the web: www. changed.Coene@siemens. we µll consider it for a next version.atea. let us know.be.atea. may be used. support can be directed to: Lode Coene: Email: Lode. If you have a great idea to be used in SUA.01. suggestions.be/sua Thank you 24 SUA tutorial 04.Verwimp@siemens. sctp. 25 http://www.Information and Communication Networks .. GSM goes around the world SS7 makes it work http://www.sctp.01..2011 © Siemens Atea . And now for something completely different...de SUA tutorial 04...be/sua .And SMS is the mobile data revolution.