由于协议问题,在与我司产品对接时E厂商R路由器产生大量BFD告警

发布时间:  2012-12-17 浏览次数:  66 下载次数:  0
问题描述

随着运营商对网络的IP化改造,BFD技术也越来越多的得到了应用,我司产品也不可避免的要和多家友商进行BFD的对接。在与E厂商R系列路由器的对接中,发现其路由器不断报如下错误:

Feb 21 15:06:53.231: [0000]: %RSVP-7-PING: [rsvp_lsp_ping_handler] received a mpls ping for endpoint 10.0.1.15, tunnel_id 108 extended tunnel_id 10.0.1.4, sender 10.0.11.26 lsp_id 1

 

Feb 21 15:06:53.231: [0000]: %RSVP-7-PING: [rsvp_lsp_ping_handler]  in interface 10.0.12.17 in nbr 10.0.1.15

 

Feb 21 15:06:53.232: [0000]: %RSVP-7-PING: [rsvp_lsp_ping_handler] RSVP returns code 3 in interface 10.0.12.17 in nbr 10.0.1.15 out interface 0.0.0.0 out nbr 0.0.0.0 out_mtu 0

 

Feb 21 15:06:53.232: %LM-3-ERR: Unsupported Echo request tlv 15 - reply with error code
处理过程

1.基于对关键报错信息“ Unsupported Echo request tlv 15 - reply with error code

”的进一步确认,E厂商工程师的解释是:在RFC4379中,只定义了1 - 10的TLV,所以他们的设备在收到我司TLV = 15的报文后无法识别,导致报错。

RFC 4379中TLV定义如下:

7.2.  TLVs

TLVs and sub-TLVs defined in this document are the following:

         Type       Sub-Type        Value Field

         ----       --------        -----------

            1                       Target FEC Stack

                         1          LDP IPv4 prefix

                         2          LDP IPv6 prefix

                         3          RSVP IPv4 LSP

                         4          RSVP IPv6 LSP

                         5          Not Assigned

                         6          VPN IPv4 prefix

                         7          VPN IPv6 prefix

                         8          L2 VPN endpoint

                         9          "FEC 128" Pseudowire (Deprecated)

                        10          "FEC 128" Pseudowire

                        11          "FEC 129" Pseudowire

                        12          BGP labeled IPv4 prefix

                        13          BGP labeled IPv6 prefix

                        14          Generic IPv4 prefix

                        15          Generic IPv6 prefix

                        16          Nil FEC

            2                       Downstream Mapping

            3                       Pad

            4                       Not Assigned

            5                       Vendor Enterprise Number

            6                       Not Assigned

            7                       Interface and Label Stack

            8                       Not Assigned

            9                       Errored TLVs

                    Any value       The TLV not understood

           10                       Reply TOS Byte

而在咨询了我司BFD专家后得出的结论是,我们这边也是按照协议做的,其中RFC5884说明了IANA规定lsp ping报文中的BFD描述符的TLV类型值为15,所以此告警的产生,应该是E厂商R系列路由器不支持此RFC所致。

RFC 5884中相关定义:

6.1.  BFD Discriminator TLV in LSP Ping

   LSP Ping Echo request and Echo reply messages carry a BFD

   discriminator TLV for the purpose of session establishment as

   described above.  IANA has assigned a type value of 15 to this TLV.

   This TLV has a length of 4.  The value contains the 4-byte local

   discriminator that the LSR, sending the LSP Ping message, associates

   with the BFD session.

   If the BFD session is not in UP state, the periodic LSP Ping Echo

   request messages MUST include the BFD Discriminator TLV.
根因
此问题是由于友商不支持最新RFC所致,需要其进行版本升级。
解决方案

升级友商设备。

建议与总结
在与友商设备的对接中,要深入了解协议的实现规定,避免友商由其自身设备的一些原因导致问题造成对接失败。

END