Network Working Group                                          A. Durand
Request for Comments: 3053                         SUN Microsystems, Inc
Category: Informational                                        P. Fasano
                                                             I. Guardini
                                                            CSELT S.p.A.
                                                                D. Lento
                                                            January 2001
Network Working Group                                          A. Durand
Request for Comments: 3053                         SUN Microsystems, Inc
Category: Informational                                        P. Fasano
                                                             I. Guardini
                                                            CSELT S.p.A.
                                                                D. Lento
                                                            January 2001

IPv6 Tunnel Broker


Status of this Memo


This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited.


Copyright Notice


Copyright (C) The Internet Society (2001). All Rights Reserved.




The IPv6 global Internet as of today uses a lot of tunnels over the existing IPv4 infrastructure. Those tunnels are difficult to configure and maintain in a large scale environment. The 6bone has proven that large sites and Internet Service Providers (ISPs) can do it, but this process is too complex for the isolated end user who already has an IPv4 connection and would like to enter the IPv6 world. The motivation for the development of the tunnel broker model is to help early IPv6 adopters to hook up to an existing IPv6 network (e.g., the 6bone) and to get stable, permanent IPv6 addresses and DNS names. The concept of the tunnel broker was first presented at Orlando's IETF in December 1998. Two implementations were demonstrated during the Grenoble IPng & NGtrans interim meeting in February 1999.


1. Introduction
1. 介绍

The growth of IPv6 networks started mainly using the transport facilities offered by the current Internet. This led to the development of several techniques to manage IPv6 over IPv4 tunnels. At present most of the 6bone network is built using manually configured tunnels over the Internet. The main drawback of this approach is the overwhelming management load for network administrators, who have to perform extensive manual configuration for each tunnel. Several attempts to reduce this management overhead


have already been proposed and each of them presents interesting advantages but also solves different problems than the Tunnel Broker, or poses drawbacks not present in the Tunnel Broker:


- the use of automatic tunnels with IPv4 compatible addresses [1] is a simple mechanism to establish early IPv6 connectivity among isolated dual-stack hosts and/or routers. The problem with this approach is that it does not solve the address exhaustion problem of IPv4. Also there is a great fear to include the complete IPv4 routing table into the IPv6 world because this would worsen the routing table size problem multiplying it by 5;

- 使用具有IPv4兼容地址的自动隧道[1]是在隔离的双栈主机和/或路由器之间建立早期IPv6连接的一种简单机制。这种方法的问题在于它不能解决IPv4的地址耗尽问题。此外,人们还非常担心将完整的IPv4路由表纳入IPv6世界,因为这会加剧路由表大小问题,将其乘以5;

- 6over4 [2] is a site local transition mechanism based on the use of IPv4 multicast as a virtual link layer. It does not solve the problem of connecting an isolated user to the global IPv6 Internet;

- 6over4[2]是一种基于使用IPv4多播作为虚拟链路层的站点本地转换机制。它不能解决将孤立用户连接到全球IPv6 Internet的问题;

- 6to4 [3] has been designed to allow isolated IPv6 domains, attached to a wide area network with no native IPv6 support (e.g., the IPv4 Internet), to communicate with other such IPv6 domains with minimal manual configuration. The idea is to embed IPv4 tunnel addresses into the IPv6 prefixes so that any domain border router can automatically discover tunnel endpoints for outbound IPv6 traffic.

- 6to4[3]的设计允许连接到广域网且不支持本机IPv6(如IPv4互联网)的独立IPv6域以最少的手动配置与其他此类IPv6域通信。其想法是将IPv4隧道地址嵌入IPv6前缀中,以便任何域边界路由器都可以自动发现出站IPv6流量的隧道端点。

The Tunnel Broker idea is an alternative approach based on the provision of dedicated servers, called Tunnel Brokers, to automatically manage tunnel requests coming from the users. This approach is expected to be useful to stimulate the growth of IPv6 interconnected hosts and to allow early IPv6 network providers to provide easy access to their IPv6 networks.


The main difference between the Tunnel Broker and the 6to4 mechanisms is that the they serve a different segment of the IPv6 community:


- the Tunnel Broker fits well for small isolated IPv6 sites, and especially isolated IPv6 hosts on the IPv4 Internet, that want to easily connect to an existing IPv6 network;

- 隧道代理非常适合小型孤立的IPv6站点,特别是IPv4 Internet上的孤立IPv6主机,这些站点希望轻松连接到现有IPv6网络;

- the 6to4 approach has been designed to allow isolated IPv6 sites to easily connect together without having to wait for their IPv4 ISPs to deliver native IPv6 services. This is very well suited for extranet and virtual private networks. Using 6to4 relays, 6to4 sites can also reach sites on the IPv6 Internet.

- 6to4方法的设计目的是允许隔离的IPv6站点轻松连接在一起,而无需等待其IPv4 ISP提供本机IPv6服务。这非常适合外联网和虚拟专用网络。使用6to4中继,6to4站点还可以连接到IPv6 Internet上的站点。

In addition, the Tunnel Broker approach allows IPv6 ISPs to easily perform access control on the users enforcing their own policies on network resources utilization.

此外,隧道代理方法允许IPv6 ISP轻松地对实施自己的网络资源利用策略的用户执行访问控制。

This document is intended to present a framework describing the guidelines for the provision of a Tunnel Broker service within the Internet. It does not specify any protocol but details the general architecture of the proposed approach. It also outlines a set of viable alternatives for implementing it. Section 2 provides an overall description of the Tunnel Broker model; Section 3 reports known limitations to the model; Section 4 briefly outlines other possible applications of the Tunnel Broker approach; Section 5 addresses security issues.


2. Tunnel Broker Model
2. 隧道经纪人模型

Tunnel brokers can be seen as virtual IPv6 ISPs, providing IPv6 connectivity to users already connected to the IPv4 Internet. In the emerging IPv6 Internet it is expected that many tunnel brokers will be available so that the user will just have to pick one. The list of the tunnel brokers should be referenced on a "well known" web page (e.g. on to allow users to choose the "closest" one, the "cheapest" one, or any other one.

隧道代理可以被视为虚拟IPv6 ISP,为已经连接到IPv4 Internet的用户提供IPv6连接。在新兴的IPv6互联网中,预计将有许多隧道代理可用,因此用户只需选择一个即可。隧道经纪人名单应在“知名”网页(如允许用户选择“最近的”、“最便宜的”或任何其他。

The tunnel broker model is based on the set of functional elements depicted in figure 1.


                                          / |server|
                                         /  |      |
                                        /   +------+
              +----------+     +------+/    +------+
              |dual-stack|     |tunnel|     |tunnel|
              |   node   |<--->|broker|<--->|server|
              |  (user)  |     |      |     |      |
              +----------+     +------+\    +------+
                                  |     \   +------+
            tunnel end-point      v      \  |tunnel|
                  /\            +---+     \ |server|
                  ||            |DNS|      \|      |
                  ||            +---+       +------+
                  ||                    tunnel end-point
                  ||                           /\
                  ||                           ||
                       IPv6 over IPv4 tunnel
                                          / |server|
                                         /  |      |
                                        /   +------+
              +----------+     +------+/    +------+
              |dual-stack|     |tunnel|     |tunnel|
              |   node   |<--->|broker|<--->|server|
              |  (user)  |     |      |     |      |
              +----------+     +------+\    +------+
                                  |     \   +------+
            tunnel end-point      v      \  |tunnel|
                  /\            +---+     \ |server|
                  ||            |DNS|      \|      |
                  ||            +---+       +------+
                  ||                    tunnel end-point
                  ||                           /\
                  ||                           ||
                       IPv6 over IPv4 tunnel

Figure 1: the Tunnel Broker model


2.1 Tunnel Broker (TB)
2.1 隧道代理(TB)

The TB is the place where the user connects to register and activate tunnels. The TB manages tunnel creation, modification and deletion on behalf of the user.


For scalability reasons the tunnel broker can share the load of network side tunnel end-points among several tunnel servers. It sends configuration orders to the relevant tunnel server whenever a tunnel has to be created, modified or deleted. The TB may also register the user IPv6 address and name in the DNS.


A TB must be IPv4 addressable. It may also be IPv6 addressable, but this is not mandatory. Communications between the broker and the servers can take place either with IPv4 or IPv6.


2.2 Tunnel server (TS)
2.2 隧道服务器(TS)

A TS is a dual-stack (IPv4 & IPv6) router connected to the global Internet. Upon receipt of a configuration order coming from the TB, it creates, modifies or deletes the server side of each tunnel. It may also maintain usage statistics for every active tunnel.


2.3 Using the Tunnel Broker
2.3 使用隧道代理

The client of the Tunnel Broker service is a dual-stack IPv6 node (host or router) connected to the IPv4 Internet. Approaching the TB, the client should be asked first of all to provide its identity and credentials so that proper user authentication, authorization and (optionally) accounting can be carried out (e.g., relying on existing AAA facilities such as RADIUS). This means that the client and the TB have to share a pre-configured or automatically established security association to be used to prevent unauthorized use of the service. With this respect the TB can be seen as an access-control server for IPv4 interconnected IPv6 users.

隧道代理服务的客户端是连接到IPv4 Internet的双堆栈IPv6节点(主机或路由器)。接近TB时,应首先要求客户提供其身份和凭证,以便进行适当的用户身份验证、授权和(可选)记帐(例如,依赖现有AAA设施,如RADIUS)。这意味着客户端和TB必须共享预配置或自动建立的安全关联,以防止未经授权使用服务。在这方面,TB可以被视为IPv4互连IPv6用户的访问控制服务器。

Once the client has been authorized to access the service, it should provide at least the following information:


- the IPv4 address of the client side of the tunnel;

- 隧道客户端的IPv4地址;

- a name to be used for the registration in the DNS of the global IPv6 address assigned to the client side of the tunnel;

- 用于在DNS中注册分配给隧道客户端的全局IPv6地址的名称;

- the client function (i.e., standalone host or router).

- 客户端功能(即独立主机或路由器)。

Moreover, if the client machine is an IPv6 router willing to provide connectivity to several IPv6 hosts, the client should be asked also to provide some information about the amount of IPv6 addresses required. This allows the TB to allocate the client an IPv6 prefix that fits its needs instead of a single IPv6 address.


The TB manages the client requests as follows:


- it first designates (e.g., according to some load sharing criteria defined by the TB administrator) a Tunnel Server to be used as the actual tunnel end-point at the network side;

- 它首先指定(例如,根据TB管理员定义的一些负载共享标准)一个隧道服务器作为网络侧的实际隧道端点;

- it chooses the IPv6 prefix to be allocated to the client; the prefix length can be anything between 0 and 128, most common values being 48 (site prefix), 64 (subnet prefix) or 128 (host prefix);

- 选择要分配给客户端的IPv6前缀;前缀长度可以是0到128之间的任何值,最常见的值是48(站点前缀)、64(子网前缀)或128(主机前缀);

- it fixes a lifetime for the tunnel;

- 它确定了隧道的寿命;

- it automatically registers in the DNS the global IPv6 addresses assigned to the tunnel end-points;

- 它自动在DNS中注册分配给隧道端点的全局IPv6地址;

- it configures the server side of the tunnel;

- 它配置隧道的服务器端;

- it notifies the relevant configuration information to the client, including tunnel parameters and DNS names.

- 它向客户端通知相关配置信息,包括隧道参数和DNS名称。

After the above configuration steps have been carried out (including the configuration of the client), the IPv6 over IPv4 tunnel between the client host/router and the selected TS is up and working, thus allowing the tunnel broker user to get access to the 6bone or any other IPv6 network the TS is connected to.

执行上述配置步骤(包括客户端的配置)后,客户端主机/路由器和所选TS之间的IPv6 over IPv4隧道启动并工作,从而允许隧道代理用户访问TS连接的6bone或任何其他IPv6网络。

2.4 IPv6 address assignment
2.4 IPv6地址分配

The IPv6 addresses assigned to both sides of each tunnel must be global IPv6 addresses belonging to the IPv6 addressing space managed by the TB.


The lifetime of these IPv6 addresses should be relatively long and potentially longer than the lifetime of the IPv4 connection of the user. This is to allow the client to get semipermanent IPv6 addresses and associated DNS names even though it is connected to the Internet via a dial-up link and gets dynamically assigned IPv4 addresses through DHCP.


2.5 Tunnel management
2.5 隧道管理

Active tunnels consume precious resources on the tunnel servers in terms of memory and processing time. For this reason it is advisable to keep the number of unused tunnels as small as possible deploying a well designed tunnel management mechanism.


Each IPv6 over IPv4 tunnel created by the TB should at least be assigned a lifetime and removed after its expiration unless an explicit lifetime extension request is submitted by the client.

TB创建的每个IPv6 over IPv4隧道应至少分配一个生存期,并在其到期后删除,除非客户端提交显式的生存期扩展请求。

Obviously this is not an optimal solution especially for users accessing the Internet through short-lived and dynamically addressed IPv4 connections (e.g., dial-up links). In this case a newly established tunnel is likely to be used just for a short time and then never again, in that every time the user reconnects he gets a new IPv4 address and is therefore obliged either to set-up a new tunnel or to update the configuration of the previous one. In such a situation a more effective tunnel management may be achieved by having the TS periodically deliver to the TB IPv6 traffic and reachability statistics for every active tunnel. In this way, the TB can enforce a tunnel deletion after a period of inactivity without waiting for the expiration of the related lifetime which can be relatively longer (e.g., several days).


Another solution may be to implement some kind of tunnel management protocol or keep-alive mechanism between the client and the TS (or between the client and the TB) so that each tunnel can be immediately released after the user disconnects (e.g., removing his tunnel end-point or tearing down his IPv4 connection to the Internet). The drawback of this policy mechanism is that it also requires a software upgrade on the client machine in order to add support for the ad-hoc keep-alive mechanism described above.

另一种解决方案可能是在客户端和TS(或客户端和TB)之间实施某种隧道管理协议或保持活动机制,以便在用户断开连接(例如,移除其隧道端点或断开其到Internet的IPv4连接)后立即释放每个隧道。此策略机制的缺点是,它还需要在客户端计算机上进行软件升级,以便添加对上述ad-hoc keep-alive机制的支持。

Moreover, keeping track of the tunnel configuration even after the user has disconnected from the IPv4 Internet may be worth the extra cost. In this way, in fact, when the user reconnects to the Internet, possibly using a different IPv4 address, he could just restart the tunnel by getting in touch with the TB again. The TB could then order a TS to re-create the tunnel using the new IPv4 address of the client but reusing the previously allocated IPv6 addresses. That way, the client could preserve a nearly permanent (static) IPv6 address even though its IPv4 address is dynamic. It could also preserve the associated DNS name.

此外,即使在用户已断开与IPv4 Internet的连接之后,也要跟踪隧道配置,这可能值得付出额外的成本。事实上,通过这种方式,当用户重新连接到Internet时(可能使用不同的IPv4地址),他可以通过再次联系TB重新启动隧道。然后,TB可以命令TS使用客户端的新IPv4地址重新创建隧道,但重用先前分配的IPv6地址。这样,客户机可以保留一个几乎永久(静态)的IPv6地址,即使其IPv4地址是动态的。它还可以保留关联的DNS名称。

2.6 Interactions between client, TB, TS and DNS
2.6 客户端、TB、TS和DNS之间的交互

As previously stated, the definition of a specific set of protocols and procedures to be used for the communication among the various entities in the Tunnel Broker architecture is outside of the scope of the present framework document. Nevertheless, in the reminder of this section some viable technical alternatives to support client-TB, TB-TS and TB-DNS interactions are briefly described in order to help future implementation efforts or standardization initiatives.


The interaction between the TB and the user could be based on http. For example the user could provide the relevant configuration information (i.e., the IPv4 address of the client side of the tunnel, etc.) by just filling up some forms on a Web server running on the TB. As a result the server could respond with an html page stating that the server end-point of the tunnel is configured and displaying all the relevant tunnel information.


After that, the most trivial approach would be to leave the user to configure the client end-point of the tunnel on his own. However, it should be highly valuable to support a mechanism to automate this procedure as much as possible.


Several options may be envisaged to assist the Tunnel Broker user in the configuration of his dual-stack equipment. The simplest option is that the TB could just prepare personalized activation and de-activation scripts to be run off-line on the client machine to achieve easy set-up of the client side tunnel end-point. This


solution is clearly the easiest to implement and operate in that it does not require any software extension on the client machine. However, it raises several security concerns because it may be difficult for the user to verify that previously downloaded scripts do not perform illegal or dangerous operations once executed.


The above described security issues could be elegantly overcome by defining a new MIME (Multipurpose Internet Mail Extension) content-type (e.g., application/tunnel) [4,5] to be used by the TB to deliver the tunnel parameters to the client. In this case, there must be a dedicated agent running on the client to process this information and actually set-up the tunnel end-point on behalf of the user. This is a very attractive approach which is worth envisaging. In particular, the definition of the new content-type might be the subject of a future ad-hoc document.


Several options are available also to achieve proper interaction between the broker and the Tunnel Servers. For example a set of simple RSH commands over IPsec could be used for this purpose. Another alternative could be to use SNMP or to adopt any other network management solution.


Finally, the Dynamic DNS Update protocol [6] should be used for automatic DNS update (i.e., to add or delete AAAA, A6 and PTR records from the DNS zone reserved for Tunnel Broker users) controlled by the TB. A simple alternative would be for the TB to use a small set of RSH commands to dynamically update the direct and inverse databases on the authoritative DNS server for the Tunnel Broker users zone (e.g.


2.7 Open issues
2.7 公开问题

Real usage of the TB service may require the introduction of accounting/billing functions.


3. Known limitations
3. 已知的限制

This mechanism may not work if the user is using private IPv4 addresses behind a NAT box.


4. Use of the tunnel broker concept in other areas
4. 隧道代理概念在其他领域的应用

The Tunnel Broker approach might be efficiently exploited also to automatically set-up and manage any other kind of tunnel, such as a multicast tunnel (e.g., used to interconnect multicast islands within the unicast Internet) or an IPsec tunnel.


Moreover, the idea of deploying a dedicated access-control server, like the TB, to securely authorize and assist users that want to gain access to an IPv6 network might prove useful also to enhance other transition mechanisms. For example it would be possible to exploit a similar approach within the 6to4 model to achieve easy relay discovery. This would make life easier for early 6to4 adopters but would also allow the ISPs to better control the usage of their 6to4 relay facilities (e.g., setting up appropriate usage policies).


5. Security Considerations
5. 安全考虑

All the interactions between the functional elements of the proposed architecture need to be secured:


- the interaction between the client and TB;

- 客户与结核病之间的互动;

- the interaction between the TB and the Tunnel Server;

- TB与隧道服务器之间的交互;

- the interaction between the TB and the DNS.

- TB和DNS之间的交互。

The security techniques adopted for each of the required interactions is dependent on the implementation choices.


For the client-TB interaction, the usage of http allows the exploitation of widely adopted security features, such as SSL (Secure Socket Layer) [7], to encrypt data sent to and downloaded from the web server. This also makes it possible to rely on a simple "username" and "password" authentication procedure and on existing AAA facilities (e.g., RADIUS) to enforce access-control.


For the TB-TS interaction secure SNMP could be adopted [8,9,10]. If the dynamic DNS update procedure is used for the TB-DNS interaction, the security issues are the same as discussed in [11]. Otherwise, if a simpler approach based on RSH commands is used, standard IPsec mechanisms can be applied [12].


Furthermore, if the configuration of the client is achieved running scripts provided by the TB, these scripts must be executed with enough privileges to manage network interfaces, such as an administrator/root role. This can be dangerous and should be considered only for early implementations of the Tunnel Broker approach. Transferring tunnel configuration parameters in a MIME type over https is a more secure approach.


In addition a loss of confidentiality may occur whenever a dial-up user disconnects from the Internet without tearing down the tunnel previously established through the TB. In fact, the TS keeps tunneling the IPv6 traffic addressed to that user to his old IPv4


address regardless of the fact that in the meanwhile that IPv4 address could have been dynamically assigned to another subscriber of the same dial-up ISP. This problem could be solved by implementing on every tunnel the keep-alive mechanism outlined in section 2.5 thus allowing the TB to immediately stop IPv6 traffic forwarding towards disconnected users.


Finally TBs must implement protections against denial of service attacks which may occur whenever a malicious user exhausts all the resources available on the tunnels server by asking for a lot of tunnels to be established altogether. A possible protection against this attack could be achieved by administratively limiting the number of tunnels that a single user is allowed to set-up at the same time.


6. Acknowledgments
6. 致谢

Some of the ideas refining the tunnel broker model came from discussion with Perry Metzger and Marc Blanchet.

改进隧道经纪人模型的一些想法来自于与佩里·梅茨格(Perry Metzger)和马克·布兰切特(Marc Blanchet)的讨论。

7. References
7. 工具书类

[1] Gilligan, R. and E. Nordmark, "Transition Mechanisms for IPv6 Hosts and Routers", RFC 1933, April 1996.

[1] Gilligan,R.和E.Nordmark,“IPv6主机和路由器的过渡机制”,RFC 1933,1996年4月。

[2] Carpenter, B. and C. Jung, "Transmission of IPv6 over IPv4 Domains without Explicit Tunnels", RFC 2529, March 1999.

[2] Carpenter,B.和C.Jung,“无显式隧道的IPv4域上IPv6传输”,RFC 2529,1999年3月。

[3] Carpenter, B. and K. Moore, "Connection of IPv6 Domains via IPv4 Clouds without Explicit Tunnels", Work in Progress.

[3] Carpenter,B.和K.Moore,“通过IPv4云连接IPv6域而无显式隧道”,工作正在进行中。

[4] Freed, N. and N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies, RFC 2045, November 1996.

[4] Freed,N.和N.Borenstein,“多用途互联网邮件扩展(MIME)第一部分:互联网邮件正文格式,RFC 20451996年11月。

[5] Freed, N. and N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types", RFC 2046, November 1996.

[5] Freed,N.和N.Borenstein,“多用途互联网邮件扩展(MIME)第二部分:媒体类型”,RFC 20461996年11月。

[6] Vixie, P., Editor, Thomson, T., Rekhter, Y. and J. Bound, "Dynamic Updates in the Domain Name System (DNS UPDATE)", RFC 2136, April 1997.

[6] Vixie,P.,编辑,Thomson,T.,Rekhter,Y.和J.Bound,“域名系统中的动态更新(DNS更新)”,RFC 21361997年4月。

[7] Guttman, E., Leong, L. and G. Malkin, "Users' Security Handbook", FYI 34, RFC 2504, February 1999.

[7] Guttman,E.,Leong,L.和G.Malkin,“用户安全手册”,FYI 34,RFC 2504,1999年2月。

[8] Wijnen, B., Harrington, D. and R. Presuhn, "An Architecture for Describing SNMP Management Frameworks", RFC 2571, April 1999.

[8] Wijnen,B.,Harrington,D.和R.Presuhn,“描述SNMP管理框架的体系结构”,RFC 2571,1999年4月。

[9] Blumenthal, U. and B. Wijnen, "User-based Security Model (USM) for version 3 of the Simple Network Management Protocol (SNMPv3)", RFC 2574, April 1999.

[9] Blumenthal,U.和B.Wijnen,“简单网络管理协议(SNMPv3)第3版的基于用户的安全模型(USM)”,RFC 2574,1999年4月。

[10] Wijnen, B., Presuhn, R. and K. McCloghrie, "View-based Access Control Model (VACM) for the Simple Network Management Protocol (SNMP)", RFC 2575, April 1999.

[10] Wijnen,B.,Presuhn,R.和K.McCloghrie,“用于简单网络管理协议(SNMP)的基于视图的访问控制模型(VACM)”,RFC2575,1999年4月。

[11] Eastlake, D., "Secure Domain Name System Dynamic Update", RFC 2137, April 1997.

[11] Eastlake,D.,“安全域名系统动态更新”,RFC 2137,1997年4月。

[12] Kent, S. and R. Atkinson, "Security Architecture for the Internet Protocol", RFC 2401, November 1998.

[12] Kent,S.和R.Atkinson,“互联网协议的安全架构”,RFC 2401,1998年11月。

8. Authors' Addresses
8. 作者地址

Alain Durand SUN Microsystems, Inc 901 San Antonio Road MPK17-202 Palo Alto, CA 94303-4900 USA

美国加利福尼亚州帕洛阿尔托市圣安东尼奥路901号Alain Durand SUN Microsystems,Inc.MPK17-202,邮编94303-4900

   Phone: +1 650 786 7503
   Phone: +1 650 786 7503

Paolo Fasano S.p.A. CSELT S.p.A. Switching and Network Services - Networking via G. Reiss Romoli, 274 10148 TORINO Italy

Paolo Fasano S.p.A.CSELT S.p.A.交换和网络服务-通过G.Reiss Romoli进行网络连接,意大利都灵274 10148

   Phone: +39 011 2285071
   Phone: +39 011 2285071

Ivano Guardini CSELT S.p.A. Switching and Network Services - Networking via G. Reiss Romoli, 274 10148 TORINO Italy

Ivano Guardini CSELT S.p.A.交换和网络服务-通过G.Reiss Romoli联网,274 10148意大利都灵

   Phone: +39 011 2285424
   Phone: +39 011 2285424

Domenico Lento TIM Business Unit Project Management via Orsini, 9 90100 Palermo Italy

Domenico Lento TIM事业部项目管理部via Orsini,9 90100意大利巴勒莫

   Phone: +39 091 7583243
   Phone: +39 091 7583243
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