Next generation carriers internet backbone node ... - IEEE Xplore

Next Generation Carriers Internet Backbone Node Architecture (MSN Type-X) Michihiro AOKI, Naoaki YAMANAKA, Takashi KURIMOTO, Takashi MIYAMURA, Jun NISHIKIDO NTT Network Service Systems Laboratories 3-9-1 1, Midori-cho, Musashmo-shi, Tokyo, 180-8585, Japan

Abstract Next generation carriers Internet backbone node arclutecture are proposed that offer sophisticated QoS support including real time voice, video streaming, and VPN. The backbone core node, MSN (Multi-service network) Type-X, has 320 Gb/s throughput and IP V4N6 dual stack forwarding capability and OC-192C full wire-rate forwarding performance. In addition, sophisticated DiiXServ having 4096 virtual queue realizing full hardware is also proposed. In addition, Type-X has ATM emulation techmque. Finally, the paper describes high-reliability technique such as newly structure non-stop software and f i i w a r e up grade technique. This newly proposed technique and system offers next generation, real time, high-QoS capability.

1.

Introduction

3.

IP traffic is growing at an exponential rate. Toward the data-centric public network, all-packet networks that use an IP-based backbone network are being constructed. To realize the backbone network, large-scale routers with soplusticated QoS control functions are a key component. For these routers, there are two main requirements (1)scalability and (2) QoS support. Several researches and systems are reported for the back bone [1]-[SI. Our research project is motivated by the above observation. We are now developing backbone switch routers with multi-QoS support. There are two types of backbone routers; we call them, Type-S and Type-X. Type-S is the small size core router for terminated subscriber functions (at the edge) [9][101. Type- X, on the other hand, is pure backbone transit router [ 111, This paper describes a multi-service network architecture as well as detailed backbone router, Type-X architectures. Type-X is 320 Gb/s IF’V4N6 dual stack, full wire rate machine. It has well sophisticated QoS support. In this paper, QoS, ATM emulation and reliability technique are described.

2.

Network) architecture is used as shown in Fig. 1. In MSN, different networks such as S T M or data networks are converted to the IP-centric packet network by MG (Media Gateway). Call control and other sophisticated control functions are performed at the CA (Call or Control Agent). For packet transport, the core network is realized using high-performance packet routers with QoS support. Backbone core network, there are two types of core switch/router are used. One is small size core/edge switch named Type-S [11 and another is large transit MPLS LER named Type-X. Type-S has 5 - 40 Gb/s throughput with law speed line interface. On the other hand, Type-X has 2.4 - 10 Gb/s high-speed interface and total 320 G/S high scalable switching throughput. This paper describes the next generation IP backbone switchhouter architecture, Type-X in detail.

Backbone core node

Type-X has a 320 Gb/s throughput, very-largecapacity router capability. It has a 16 x 10 Gb/s interface that has full-wire-rate IP packet forwarding for IP V4N6 capability, MPLS transit switch function (also with fullwire-rate) is also supported. In addition, the IP-packetbased switching offers ATM emulation, i.e. ATM switch and transit functions. However, ATM cells are not switched and transferred individually.

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To support IP service and to achieve high performance packet transfer capability, the all-packet network architecture named MSN (Multi-service

IPnetwork archtecture, MSN - 1N l T s next generahon * N.YAMANAKA is now with NTT Network Inovation Laboratories Fig.

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ATM cells are encapsulated in and transferred as same method as IP packets. Outline specifications and block diagrams are shown in Table 1 and Fig. 2. Type-X has carrier class functions for backbone node. It has full wire-rate forwarding capability under OC192C, 10 Gb/s wire both for IP V4 and IP V6 packet. NTT will introduce P V6 service for supporting security functions. On the other hand, QoS is very important function for next generation VPN and real time service. Type-X has sophisticated Dimerv queue, named Advanced DBServ (Ad-DiflServ), having 4096 virtual queues. Using AdDiffServ, new VPN service and new fair-share service based on the tariff can be supported. Detail is described in session 4. Carrier backbone transfer multi-media service including mission critical services such as banking and trade. To meet these needs, Type-X has full hardwired redundancy with non-stop active-stand by functions. In addition, Type-X employs non-stop software and firmware up grade functions. Conventional router need reset after software up grade. Backbone system strictly limited this stop operating time. This function carries world faircst product for high-reliability backbone system.

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Fig2 Block diagram of high-performance IP backbone switchhouter, Type-X Finally, Type-X has a variety of interfaces. To introduce conventional carrier's service into next generation packet backbone, real time voice transfer as well as ATM leased line service can be possible. NTT has a ATM leased line services, Mega-link and Sharelink service. Both services can be supported by MPLS encapsulate function.

4.

Table 1 Type-X functions

Advanced functions for Type-x

4.1.

Specifications Large size, backbone switchhouter Basic MPLS backbone LSR functions Throughput 80 - 320 Gb/S 96 MPPS (6 MPPY2.4 G) - 392 MPPS (24.5 MPPS/lO G) Interface OC - 192C/STM 64 (POS) OC - 48 C/STM 16 (POS/ATM) OC - 12 C/STM 4 (POS/ATM) 10 Gigabit Ethernet Gigabit Ethernet 10/100 M Ethernet Forwarding IPv4, IPv6 dual stack Full-wire rate up to OC - 192 C Full hardware forwarding Routing FUP 2, RIpng, OSPFv3, BGP4, BGP4+ protocol Buffer Advanced DiEServ. control Traflic Load balancing (MPLS path) control Reliability Full hardware redundancy Non-stop software/firmwareupgrade Power DC-48V, AC-l00/200V supply Dimension 19 inch lack

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Sophisticated QoS support, AdvancedDiffServ

Type-X nodes consist of an input line card, fixed size packet core switch, and output h e card. The input line card hosts Advanced DlffServ. Details of Ad-DiffServ are described below. Network services provided by Type-X are illustrated in Fig. 3. Today's Internet can support only best effort services such as e-mail and WWW access. However, next generation Internet services will require higher network reliability. The network should also support business services such as VPN and mission-critical

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ATM leased line service F i g 3 Various kinds of services integrated on the all-packet

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services. In addition, ATM services are becoming popular, especially as a leased line application. We also note that the ATM access technique will be used in the subscriber line, for example, XDSL and next generation mobile networks. Accordingly, Type-X supports ATM emulation, i.e. tunneling the ATM bearer connection using an IP QoS pipe. Let's look at the services supported by Type-X in more detail. They are supported by various combinations of native IP, native ATM, and ATM emulation techniques. Best effort IP service is the major service for today's IP network. Of course, the service can be supported by pure IP as shown in Fig. 4. Type-X supports Advanced DiffServ and so can provide IP-based EF (Expedited Forwarding), AF (Assured Forwarding), and BE (Best Effort) services like standard DiffServ. Recent business services such as VPN and other business data services need guaranteed IP or high-quality IP services. High quality means that the bandwidth is guaranteed. It is easily achieved in combination of ATM-CBR and IP-based EF class service. Both ATMCBR and IP-EF can guarantee the connection bandwidth. We employ the MPLS protocol to establish cut-through connections from edge to edge. Finally, NTT is now supporting various ATM bearer services. Type-X offers ATM emulation that is ATM cells are carried as P packet. For supporting the ATM bearer service, sophisticated buffer control is needed. This function is realized by the newly proposed Advanced D m e r v (Ad-DiffServ). Ad-DiffServ can support high-performance QoS control functions. Ad-DiffServ has two EF classes, six AF classes with 4096 virtual queues, and one BE class. There is a strict order in priority; that is, EF has highest priority and BE has the lowest. In other words, BE packets can be sent only ifthere are no EF or AF packets. Figure 5 shows details of the queue structure and services supported by Ad-DiffServ. There are two EF classes, one can guarantee the bandwidth as well as delay

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Fig.5 Advanced Diffserv Architecture for multi-QoS IP service bound in the Same way as the conventional DiffServ's EF class. Type-X has a special EF' class that uses queues differently from the conventional EF class. The EF' queue transfers only short packets such as voice over IP packets. This allows not only bandwidth but also delay time to be guaranteed. On the other hand,there are six AF classes. Each class is sent based on the weighted round robin (WRR) mechanism. In addition, there is one special AF' class. The AF'class has 4096 logical queues controlled by the virtual WRR mechanism (Fig6,7). The conventional AF class has only 6 queues, so it is very difficult to realize per connection queuing. However, Type-X supports MPLS and connection-based queuing. It is much different from the conventional CBQ (class-based queuing). Details are described in session 4.2. Finally, best effort IP service is efficiently and economically supported by the BE queue. Sophisticated QoS support is realized by this combination of EF, EF', AF, AF' and BE classes.

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Fig.4 Type-X network provision of Best effort, guaranteed IP and ATM services

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4.3. Fig.7 V-WRR algorithm

4.2. New VPN service The proposed IP +ATM network not only supports the high-quality IP service but also new VPN services. Figure 8 shows the isolated-VPN service that bandwidth is determined bared of the tariff concept. Isolated-VPN service means each VPN bandwidth is not influenced by the number of VPN connections. In other words, VPN bandwidth is determined only VF" connection tariff. The conventional minimum-bandwidth-guarantee VPN service can guarantee only a minimum bandwidth. Idle bandwidth is equally apportioned to each VPN. On the other hand, tariff-based bandwidth is dwided up among each VPN in the proposed service. Fig3 also shows that VPN-1 tariff is lOO$/month while VPN-2 tariff is lOOO$/month. Accordingly, VPN-2 has better quality than VPN-1. Each user can be assured of the bandwidth required even if all use the same bottleneck link. This service will become the basis of the next generation ISP service and premiere IP service. 100 Kb/s/user

ATM emulation technique

Type-X is core switchhouter. Then one important function is supporting conventional ATM leased line service. In the Type-X, combination of the Ad-DBServ and MPLS capsule technique as shown in Fig.9. The emulation technique can be supported both bearer service, QoS and OAM functions.

4.4.

High reliability

4.4.1. Path protection Type-X has the function which changes a route to the pass which it prepares for as a spare in advance when a pass congestion or failure is detected. Fig10 shows path protection functions in Type-X. Type-X has a hardware function to reroute the path. Then it needs short time to reroute the path.

4.4.2. non-stop software upgrade functions To support IP premium services, Type-X provides high-reliability both from hardware implementation and software structure. Figure 11 shows non-stop software upgrade functions in Type-X. Type-X is hardware redundant system and they can change without service stopping.

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Fig. 1 1 Non-stop software upgrade functions in Type-X New software file is installed into stand by system (#1 in Fig. 11). After installing, system operation data such as connection information, IP address etc. are copied from real active system (#0 in Fig. 11). All the programs are copied and confirmed, the system is switched and #1 become active. Conventional router needs reboot for software up date but Type-X needs no reboot. Using the new architecture, Type-X can provide very high-reliabiliiy backbone switch router. 5.

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Fig. 12 Type-X overview and structure.

System

Type-X is employing one-shelf architecture. 10Interface board is inserted from front and duplicated 320 Gb/s switch board is mounted on the back side of the self. The overview of Type-X is shown in Fig. 12. The system is 1400 mm tall, 550 mm wide and 600 mm depth.

6.

Conclusions

Next generation Internet backbone node technologies and system, Type-X are highlighted. The backbone network realizes full packet backbone switchhouter. We proposes 320 Gb/s very high-speed, high-performance and high-reliability backbone switchhouter named TypeX. Type-X has IP V4N6 dual stack forwarding with OC-192, 10 Gb/s wire-speed capability. In addition, it can handle not only conventional IP service but also new premium service such as real time voice and guaranteed service. In addition Type-X has ATM emulation capability and high-reliable non stopping software, firmware upgrade. The next generation high-quality IP network will become possible if proposed nodes and archtecture are used.

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References

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