1、18 December 2008,Interoperability in and Management of a Multi-Technology Packet Transport Network,Maarten Vissers Version 0.0,Page 2,Customer Networks,Multi-Technology Packet Transport Network,Customer Network,Customer Network,Customer Network,PTN NMS,Introduction,Our industry has developed three p
2、acket transport network technologies to support transport of frame/packet based service signals as well as bit stream based service signals and created as such a Multi-Technology PTN,Page 3,MPLS-TP,MPLS Link,MPLS Tunnel,MPLS PW,Service VLAN,Customer/Client,Ethernet-TP (I),Tunnel VLAN,Service VLAN,Et
3、hernet-TP (II),Service VLAN,Tunnel MAC,(VPLS),Physical Media (802.3,G.707,G.709),Link VLAN,Physical Media (802.3,G.707,G.709),Link VLAN,Physical Media (802.3,G.707,G.709),Customer/Client,Customer/Client,PTN Technologies,Ethernet and MPLS packet technologies are extended with a Transport Profile (TP)
4、 MPLS is extended with a single transport profile, Ethernet is extended with two transport profiles (with different tunnel layer technologies: VLAN and MAC) The layer stacks for those three PTN technologies are very similar and management of these PTN variations can be unified under a single PTN Net
5、work Manager,Page 4,NTU MTU,Outer Core,Inner Core,Outer Core,Metro Edge,Metro Aggr.,Metro Core,Metro Core,Metro Aggr.,Metro Edge,GFP,Physical Media,GFP,GFP,GFP,GFP,Physical Media,Physical Media,Physical Media,Physical Media,Physical Media,Physical Media,Physical Media,METRO,METRO,CORE,Physical Media
6、,ACCESS,PTN Service (Channel) layer,PTN Tunnel (Path) layer,Customer/Client layer,Link (Section) layer,PTN Layer Stack & Unified Network Management,PTN NMS,Page 5,Services in Multi-Technology PTN,Carrier packet transport networks consists typically of access, metro and core domains Access domains ty
7、pically deploy Ethernet, metro domains deploy Ethernet or MPLS and core domains deploy MPLS technologies today The evolution of those packet network technologies into packet transport network technologies is ongoing for some time In the near future all three PTN technologies will have the same capab
8、ilities and there is no reason for carriers to deploy a single technology and thus replace existing equipment All three PTN technologies can be deployed in every domain (access, metro, core) Those multi-technology PTNs must support inter-domain LINE, TREE and LAN services, which requires interoperab
9、ility between the three PTN technologies as endpoints of each service may be in different PTN technology domains Such interoperability is required between the service (channel) layers in the three technologies; interoperability between tunnel (path) and link (section) layers in the three technologie
10、s is not required,Page 6,p2p MPLS tunnel,p2p tunnel VLAN,rmp or mp2mp service VLAN,p2p tunnel MAC,(VPLS),Customer/Client: TREE or LAN service,UNI,UNI,Ethernet-TP (I),MPLS-TP,Ethernet-TP (II),PTN Interoperability for E-TREE/E-LAN services,All three PTN technologies deploy a service VLAN to support E-
11、TREE and E-LAN services Interoperability for those services is as such guaranteed; main difference is the tag/label used to identify each service VLAN MPLS-TP: PW label, Ethernet-TP (I): VID, Ethernet-TP (II): SID,VID,SID,PW label,Page 7,p2p MPLS tunnel,p2p tunnel VLAN,p2p or p2mp service VLAN,p2p t
12、unnel MAC,Customer/Client: LINE or TREE service,UNI,UNI,Ethernet-TP (I),MPLS-TP,Ethernet-TP (II),p2p or p2mp PW,Clause 5.5/G.805 Inter Working Function,PTN Interoperability for LINE/TREE services,Two out of three PTN technologies deploy a service VLAN to support LINE and TREE services, one technolog
13、y deploys MS-PW Interoperability for those services requires service VLAN to MS-PW interworking (as per clause 5.5/G.805 “layer network interworking”) ETH/MPLS PW InterWorking function provides such interworking Similar OAM PDU formats and similar client encapsulations make interworking trivial,VID,
14、SID,PW label,Page 8,Clause 5.5/G.805 Layer Network Interworking,The objective of layer network interworking is to provide an end-to-end trail between different types of layer network trail terminations. This requires interworking of characteristic information as different layer networks have per def
15、inition different characteristic information. In general the adapted information of different layer networks for the same client layer network is also different, although this is not necessarily the case. Layer networking may therefore require the interworking of adapted information. The trail overh
16、ead of a layer network can be defined in terms of semantics and syntax. Provided that the same semantics exist in two layer networks, the trail overhead can be interworked by passing on the semantics from one layer network to the other in the appropriate syntax, as defined by the characteristic info
17、rmation. In other words layer network interworking shall be transparent for the semantics of the trail overhead. If both layer networks have a different set of semantics, the layer network interworking is restricted to the common set of semantics. The layer network interworking function has to termi
18、nate (insert, supervise) the semantics that are not interworked. Layer network interworking is accomplished through an interworking processing function as depicted in Figure 19. The interworking processing function supports an interworking link connection between two layer network connections. The i
19、nterworking link connection is special in the sense that it is asymmetric, delimited by different types of ports. It is also special because it is in general, only transparent for a specified set of client layers. An interworking link is a topological component that represents a bridge between two l
20、ayer networks. The interworking link creates a “super layer network“, defined by the complete set of access groups that can be interworked for a specified set of client layer networks.,Page 9,Example 1: TDM service,A TDM (e.g. 2 Mbit/s) LINE service is supported in Ethernet (MEF8) and MPLS (RFC4553)
21、. Both encapsulation methods are similar, which simplifies interworking of the adapted information.,p2p MPLS tunnel,p2p tunnel VLAN,p2p service VLAN,p2p tunnel MAC,2 Mbit/s (P12x_CI) service,UNI,UNI,Ethernet-TP (I),MPLS-TP,Ethernet-TP (II),p2p MS-PW,ETH,ETHPW,PW,TDM payload,RTP (optional),CESoETH CW
22、,ECID (fixed),TYPE (88-d8),SA,DA,TDM payload,RTP (optional),SAToP CW,S bit (1),MPLS-TP PW_AI,G.8021 ETH_AI,ETH OAM,MPLS-TP OAM,ID,000,1,00000010,20 3 1 8,ECID format is same as PW label format to ease interworking with MPLS according MEF8,Transmitted DA = Received SA or broadcast address,Transmitted
23、 SA = local MAC address,Transmitted ECID = Received PW label stack entry,Transmitted S-bit = Received ECID23,OAM interworking, see slide 11,E T H P W,Page 10,Example 2: E-LINE service,An Ethernet LINE service is supported in Ethernet and MPLS (RFC4558). Both encapsulation methods are similar, which
24、simplifies interworking of the adapted information.,p2p MPLS tunnel,p2p tunnel VLAN,p2p service VLAN,p2p tunnel MAC,E-LINE (ETH_CI) service,UNI,UNI,Ethernet-TP (I),MPLS-TP,Ethernet-TP (II),p2p MS-PW,ETH,ETHPW,PW,MSDU,SA,DA,MSDU,SA,DA,S bit (1),MPLS-TP PW_AI,G.8021 ETH_AI,ETH OAM,MPLS-TP OAM,Transmit
25、ted S-bit = 1,OAM interworking, see slide 11,E T H P W,CW (fixed to all-0s),Required in MPLS-TP MS-PW due to MPLS-TP OAM presence; Seq Number support is not required; SN = fixed to 0,Page 11,Example 1&2: ETH and MPLS-TP PW NCM OAM interworking,For Network Connection Monitoring (highest MEG level) it
26、 is necessary to interwork the OAM PDU Header and Payload fields. The Header fields for both technologies are known and interworking is illustrated in figure below. The Payload fields of the MPLS-TP OAM are not yet specified; if those are a copy of the ETH OAM PDU Payload fields, then interworking b
27、ecomes trivial.,p2p MPLS tunnel,p2p tunnel VLAN,p2p service VLAN,p2p tunnel MAC,E-LINE (ETH_CI) service,UNI,UNI,Ethernet-TP (I),MPLS-TP,Ethernet-TP (II),p2p PW,ETH,ETHPW,PW,OAM specific,OpCode,5-bit Version,MEL (NCM: 7),TYPE (89-02),SA,DA,EndTLV,Flags,TLV Offset,Channel Type,To Be Defined (e.g. copy
28、 of ETH OAM),Reserved,4-bit Version,0001,G.8021 ETH_CI (OAM),S bit (1),MPLS-TP PW_CI (OAM),MIP or MEP identifier for Loopback OAM,OAM PDU independent Header,OAM PDU specific Payload,OAM PDU independent Header,OAM PDU specific Payload,NCM-MEG,NCM-MEG,NCM-MEG,E T H P W,Transmitted DA = multicast addre
29、ss or for LBM TargetMIP/MEP address,Transmitted SA = local MAC address or for LBM OriginatingMEP address,Page 12,Example 1&2: ETH and MPLS-TP PW TCM OAM interworking,p2p MPLS tunnel,p2p tunnel VLAN,p2p service VLAN,p2p tunnel MAC,E-LINE (ETH_CI) service,UNI,UNI,Ethernet-TP (I),MPLS-TP,Ethernet-TP (I
30、I),p2p PW,ETH,ETHPW,PW,OAM specific,OpCode,5-bit Version,MEL (TCM: 16),TYPE (89-02),SA,DA,EndTLV,Flags,TLV Offset,Channel Type,To Be Defined,Reserved,4-bit Version,0001,Label_13 GAL,G.8021 ETH_CI (OAM),MPLS-TP PW_CI (OAM),one GAL header for PW TCM,ETH,TCM-LSP,For Tandem Connection Monitoring (interm
31、ediate MEG level) it is necessary to interwork the OAM PDU Header and Payload fields. The Header fields for both technologies are known and interworking is illustrated in figure below. The difference with the NCM OAM is the presence of a Label_13 GAL header.,E-NNI,NCM-MEG,NCM-MEG,TCM-MEG,TCM-MEG,NCM
32、-MEG,E T H P W,ACH,Page 13,Conclusion,Interworking between ETH_CI and MPLS-TP PW_CI is an example of G.805 Layer Network Interworking The addition of ETH/MPLS-TP PW interworking functions at the boundaries of Ethernet-TP and MPLS-TP domains reduces PTN network management complexity and reduces also
33、complexity of UNI-N ports in MPLS-TP equipment Interworking of ETH_AI and MPLS-TP PW_AI is trivial (i.e. not complex) due to common encapsulation methods of client signals Interworking between ETH_CI and MPLS-TP PW_CI will become trivial when MPLS-TP OAM re-uses as much as possible the Ethernet OAM PDU Payload formats Re-use of Ethernet OAM PDU payload formats has the additional advantage that existing (Ethernet OAM) hardware, firmware and software can be re-used, making MPLS-TP OAM available quickly,
