Network Working Group D. Hamilton
Request for Comments: 2641 D. Ruffen
Category: Informational Cabletron Systems Incorporated
August 1999
Network Working Group D. Hamilton
Request for Comments: 2641 D. Ruffen
Category: Informational Cabletron Systems Incorporated
August 1999
Cabletron's VlanHello Protocol Specification Version 4
Cabletron的VlanHello协议规范版本4
Status of this Memo
本备忘录的状况
This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited.
本备忘录为互联网社区提供信息。它没有规定任何类型的互联网标准。本备忘录的分发不受限制。
Copyright Notice
版权公告
Copyright (C) The Internet Society (1999). All Rights Reserved.
版权所有（C）互联网协会（1999年）。版权所有。
Abstract
摘要
The VlanHello protocol is part of the InterSwitch Message Protocol (ISMP) which provides interswitch communication between switches running Cabletron's SecureFast VLAN (SFVLAN) product. Switches use the VlanHello protocol to discover their neighboring switches and establish the topology of the switch fabric.
VlanHello协议是交换机间消息协议（ISMP）的一部分，该协议在运行Cabletron的SecureFast VLAN（SFVLAN）产品的交换机之间提供交换机间通信。交换机使用VlanHello协议来发现其相邻的交换机并建立交换机结构的拓扑。
Table of Contents
目录
1. Introduction...................................... 2
1.1 Data Conventions.............................. 2
2. VlanHello Protocol Operational Overview........... 2
2.1 Neighbor Discovery............................ 2
2.2 Port States................................... 3
2.3 Topology Events............................... 5
2.4 Timers........................................ 9
3. InterSwitch Message Protocol...................... 9
3.1 Frame Header.................................. 10
3.2 ISMP Packet Header............................ 11
3.3 ISMP Message Body............................. 12
4. Interswitch Keepalive Message..................... 13
5. Security Considerations........................... 16
6. References........................................ 16
7. Authors' Addresses................................ 16
8. Full Copyright Statement.......................... 17
1. Introduction...................................... 2
1.1 Data Conventions.............................. 2
2. VlanHello Protocol Operational Overview........... 2
2.1 Neighbor Discovery............................ 2
2.2 Port States................................... 3
2.3 Topology Events............................... 5
2.4 Timers........................................ 9
3. InterSwitch Message Protocol...................... 9
3.1 Frame Header.................................. 10
3.2 ISMP Packet Header............................ 11
3.3 ISMP Message Body............................. 12
4. Interswitch Keepalive Message..................... 13
5. Security Considerations........................... 16
6. References........................................ 16
7. Authors' Addresses................................ 16
8. Full Copyright Statement.......................... 17
This memo is being distributed to members of the Internet community in order to solicit reactions to the proposals contained herein. While the specification discussed here may not be directly relevant to the research problems of the Internet, it may be of interest to researchers and implementers.
本备忘录将分发给互联网社区的成员，以征求对本文所载建议的反应。虽然这里讨论的规范可能与互联网的研究问题没有直接关系，但研究人员和实现人员可能对此感兴趣。
The methods used in this memo to describe and picture data adhere to the standards of Internet Protocol documentation [RFC1700], in particular:
本备忘录中用于描述和描绘数据的方法符合互联网协议文件[RFC1700]的标准，尤其是：
The convention in the documentation of Internet Protocols is to express numbers in decimal and to picture data in "big-endian" order. That is, fields are described left to right, with the most significant octet on the left and the least significant octet on the right.
互联网协议文档中的惯例是以十进制表示数字，并以“大端”顺序描绘数据。也就是说，字段是从左到右描述的，最重要的八位字节在左边，最不重要的八位字节在右边。
The order of transmission of the header and data described in this document is resolved to the octet level. Whenever a diagram shows a group of octets, the order of transmission of those octets is the normal order in which they are read in English.
本文档中描述的标题和数据的传输顺序解析为八位字节级别。每当一张图表显示一组八位字节时，这些八位字节的传输顺序就是用英语读取它们的正常顺序。
Whenever an octet represents a numeric quantity the left most bit in the diagram is the high order or most significant bit. That is, the bit labeled 0 is the most significant bit.
每当一个八位组代表一个数字量时，图表中最左边的位就是高阶或最高有效位。也就是说，标记为0的位是最高有效位。
Similarly, whenever a multi-octet field represents a numeric quantity the left most bit of the whole field is the most significant bit. When a multi-octet quantity is transmitted the most significant octet is transmitted first.
类似地，每当一个多八位组字段表示一个数值时，整个字段最左边的位就是最高有效位。当传输多个八位组数量时，首先传输最重要的八位组。
Switches use the VlanHello protocol to detect their neighboring switches and establish the topology of the switch fabric.
交换机使用VlanHello协议检测其相邻交换机并建立交换机结构的拓扑。
At initialization, each switch sends an Interswitch Keepalive message out all local ports except those which have been preconfigured such that they cannot be Network ports (see Section 2.2). Then, as each switch discovers its neighboring switches via incoming Interswitch Keepalive messages, it notifies its local topology services (see Section 2.3), which then build the topology tables for the switching fabric.
在初始化时，每个交换机向所有本地端口发送一条Interswitch Keepalive消息，但预配置为不能作为网络端口的端口除外（参见第2.2节）。然后，当每个交换机通过传入的Interswitch Keepalive消息发现其相邻交换机时，它会通知其本地拓扑服务（参见第2.3节），然后这些服务会为交换结构构建拓扑表。
Each switch continues to send Interswitch Keepalive messages at regular intervals (currently 5 seconds). If a switch has not heard from one of its neighbors for some predetermined interval (see Section 2.4), notification is sent to all interested services and the neighboring switch is removed from the topology table.
每个交换机将以固定的间隔（当前为5秒）继续发送交换机间的Keepalive消息。如果某个交换机在某个预定的时间间隔内（参见第2.4节）没有收到来自其邻居的消息，则会向所有感兴趣的服务发送通知，并从拓扑表中删除该邻居交换机。
Interswitch Keepalive messages are described in Section 4.
第4节介绍了交换机间保持消息。
Each port on a switch can be in one of several different states. These states are listed below. Figure 1 shows how the port state changes within the VlanHello protocol.
交换机上的每个端口可以处于几种不同状态之一。这些国家列在下面。图1显示了VlanHello协议中端口状态的变化。
o Unknown. This is the default state of all ports at initialization.
o 未知的这是初始化时所有端口的默认状态。
o Network. A port is deemed a Network port when the switch has received an Interswitch Keepalive message over the port from one of its neighbor switches. A transition to this state triggers a Neighbor Found event, notifying the local topology servers that the interface is functioning and a 2-way conversation has been established with the neighbor.
o 网络当交换机通过端口从其一个相邻交换机接收到交换机间Keepalive消息时，端口被视为网络端口。转换到此状态会触发“发现邻居”事件，通知本地拓扑服务器接口正在运行，并且已与邻居建立双向对话。
When the last switch is lost on a Network port, the state of the switch reverts to either Network Only (see next state) or to Unknown, and a Neighbor Lost event is triggered, notifying the local topology servers that the interface is no longer operational.
当网络端口上的最后一个交换机丢失时，交换机的状态将恢复为仅网络状态（请参见下一状态）或未知状态，并触发邻居丢失事件，通知本地拓扑服务器接口不再工作。
o Network Only. Certain types of port interfaces are incapable of accessing user endstations and can only be used to access other switches. Such ports are deemed Network Only ports. If the last switch is lost from a port that has already been deemed a Network port, the VlanHello protocol checks the condition of the port interface. If it is the type of interface that can only be used to access other switches, the state of the port is set to Network Only. Otherwise, it reverts to Unknown.
o 仅网络。某些类型的端口接口无法访问用户端站，只能用于访问其他交换机。此类端口被视为仅网络端口。如果最后一个交换机从已被视为网络端口的端口丢失，VlanHello协议将检查端口接口的状态。如果接口类型只能用于访问其他交换机，则端口状态设置为“仅网络”。否则，它将恢复为未知。
o Standby. A port is deemed a Standby port under the following conditions:
o 备用物品在下列情况下，端口被视为备用端口：
o The neighbor switch on the port has a higher level of functionality and it has determined that the local switch is incompatible with that functionality. In this circumstance, the MAC entry for the local switch in the Interswitch Keepalive message received from the neighbor contains an assigned status of Incompatible.
o 端口上的邻居交换机具有更高级别的功能，并且已确定本地交换机与该功能不兼容。在这种情况下，从邻居接收的交换机间Keepalive消息中本地交换机的MAC条目包含分配的不兼容状态。
o The list of MAC entries in the Interswitch Keepalive message received from the neighbor switch does not contain an entry for the local switch. In this circumstance, the local switch assumes that communication with its neighbor will be one-way only.
o 从邻居交换机接收的交换机间Keepalive消息中的MAC条目列表不包含本地交换机的条目。在这种情况下，本地交换机假定与邻居的通信将是单向的。
The VlanHello protocol continues to listen for Interswitch Keepalive messages on a Standby port, but does not transmit any Interswitch Keepalive messages over the port. If a message is received that removes the condition under which the port state was set to Standby, the state of the port is set to Network.
VlanHello协议在备用端口上继续侦听交换机间保持消息，但不通过端口传输任何交换机间保持消息。如果收到的消息删除了端口状态设置为待机状态的条件，则端口状态将设置为网络。
o Going to Access. When any packet other than an Interswitch Keepalive message is received over an Unknown port, the state of the port is changed to Going to Access and a timer is activated. If the timer expires without an Interswitch Keepalive message being received over the port, the port state changes to Access.
o 正在访问。当通过未知端口接收到除Interswitch Keepalive消息以外的任何数据包时，该端口的状态将更改为Gong to Access并激活计时器。如果计时器过期而未通过端口接收到交换机间Keepalive消息，则端口状态将更改为Access。
o Access. A port is deemed an Access port when any packet other than an Interswitch Keepalive message has been received over the port and the Going to Access timer has expired. A port can also be administratively designated an Access "control" port, meaning the port is to remain an Access port, regardless of the type of messages that are received on it. Interswitch Keepalive messages are not sent over Access control ports.
o 通道当通过端口接收到除Interswitch Keepalive消息之外的任何数据包，并且即将访问的计时器已过期时，端口被视为访问端口。端口也可以在管理上指定为访问“控制”端口，这意味着该端口将保持为访问端口，而不管其上接收的消息类型如何。交换机间保持消息不会通过访问控制端口发送。
Three other types of ports are recognized: the host management port, host data port, and host control port. These ports are designated at initialization and are used to access the host CPU. Interswitch Keepalive messages are not sent over these ports.
可以识别其他三种类型的端口：主机管理端口、主机数据端口和主机控制端口。这些端口在初始化时指定，用于访问主机CPU。交换机间保持消息不会通过这些端口发送。
Packet in
|
V
+---------+
Packet in | Unknown |
| +---------+
G-A V |
Timer +----------+ no V
exp | Going to |<------[KA msg?] Packet in
<------| Access | | |
| +----------+ yes | V
V | V yes +---------+
+--------+ V [1-way?]------+-->| Standby |
| Access | [KA msg?] | ^ +---------+
+--------+ | | no | |
| V no | V
yes | [compatible?]----+ [KA msg?]
| | |
| | yes | yes
| V V
V +---------+ [1-way?]
+--------->| Network |<--+ |
+---------+ ^ | no
| | yes V
lost last | +<----[compatible?]
neighbor |
V
[network]
[ only? ]
|
+--------------+ yes | no +---------+
| Network Only |<-----------+----------->| Unknown |
+--------------+ +---------+
Packet in
|
V
+---------+
Packet in | Unknown |
| +---------+
G-A V |
Timer +----------+ no V
exp | Going to |<------[KA msg?] Packet in
<------| Access | | |
| +----------+ yes | V
V | V yes +---------+
+--------+ V [1-way?]------+-->| Standby |
| Access | [KA msg?] | ^ +---------+
+--------+ | | no | |
| V no | V
yes | [compatible?]----+ [KA msg?]
| | |
| | yes | yes
| V V
V +---------+ [1-way?]
+--------->| Network |<--+ |
+---------+ ^ | no
| | yes V
lost last | +<----[compatible?]
neighbor |
V
[network]
[ only? ]
|
+--------------+ yes | no +---------+
| Network Only |<-----------+----------->| Unknown |
+--------------+ +---------+
Figure 1: Port State Machine
图1：端口状态机
When the VlanHello protocol discovers new information about the status of one of its network ports, it notifies its local topology service center so that the service center can build or modify the topology tables for the switch fabric. This notification takes the form of a system event, described in a structure known as a topology relay structure. These structures are linked in a first-in/first-out (FIFO) queue and processed by the topology servers in the order in which they were received.
当VlanHello协议发现有关其一个网络端口状态的新信息时，它会通知其本地拓扑服务中心，以便服务中心可以为交换机结构构建或修改拓扑表。此通知采用系统事件的形式，在称为拓扑中继结构的结构中描述。这些结构在先进先出（FIFO）队列中链接，并由拓扑服务器按照接收顺序进行处理。
A topology relay structure typically contains information from Interswitch Keepalive messages received on the specified port, as shown below.
拓扑中继结构通常包含来自指定端口上接收的交换机间Keepalive消息的信息，如下所示。
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
00 | Event |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
04 | Delta options mask |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
08 | Current options mask |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
12 | Port number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
16 | |
+ Port neighbor switch identifier +
| |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Port neighbor IP address ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
28 | ... Port neighbor IP address | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Neighbor chassis MAC addr +
32 | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
36 | Neighbor chassis IP address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
40 | Neighbor functional level |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
44 | Topology agent |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
48 | Next event |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
00 | Event |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
04 | Delta options mask |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
08 | Current options mask |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
12 | Port number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
16 | |
+ Port neighbor switch identifier +
| |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Port neighbor IP address ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
28 | ... Port neighbor IP address | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Neighbor chassis MAC addr +
32 | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
36 | Neighbor chassis IP address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
40 | Neighbor functional level |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
44 | Topology agent |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
48 | Next event |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Event
事件
This 4-octet field contains the number of the event. Valid values are as follows:
此4个八位组字段包含事件的编号。有效值如下所示：
1 A new neighbor switch was discovered on the specified port. 2 The neighbor switch has gained the feature(s) specified in the Delta options mask. 3 The neighbor switch has lost the feature(s) specified in the Delta options mask. 4 The neighbor switch has timed out and is presumed down. 5 The specified port is down.
1在指定端口上发现新的邻居交换机。2相邻交换机已获得增量选项掩码中指定的功能。3相邻交换机已丢失增量选项掩码中指定的功能。4邻居交换机已超时，并假定已关闭。5指定端口已关闭。
6 The neighbor switch has been previously seen on a different port. The specified port is the previous port. 7 The specified port is being reassigned to another topology agent. Event is generated by the current (old) agent. 8 The port is looped -- that is, the Keepalive message was generated by the receiving switch. 9 The port is crossed -- that is, a Keepalive message was received on a port not owned by this topology agent. 10 The neighbor switch's functional level has changed. 11 The neighbor switch is running an incompatible version of the protocol. 12 Two-way communication with the neighbor switch has been lost. 13 The neighbor switch's Keepalive message sequence number has been reset, indicating the switch itself has been reset.
6以前在不同的端口上看到过相邻交换机。指定的端口是上一个端口。7指定的端口正在重新分配给另一个拓扑代理。事件由当前（旧）代理生成。8端口是循环的——也就是说，Keepalive消息是由接收交换机生成的。9端口被交叉——也就是说，在不属于此拓扑代理的端口上接收到Keepalive消息。10相邻交换机的功能级别已更改。11邻居交换机正在运行协议的不兼容版本。12与相邻交换机的双向通信已丢失。13邻居交换机的Keepalive消息序列号已重置，表明交换机本身已重置。
Delta options mask
增量选项掩码
This 4-octet field contains a bit map specifying the feature(s) gained or lost by the neighbor switch (events 2 and 3 only). Valid values are as specified for the next field, Current options mask.
此4个八位组字段包含一个位图，指定相邻交换机获得或丢失的功能（仅限事件2和3）。有效值与为下一个字段“当前选项掩码”指定的值相同。
Current options mask
当前选项掩码
This 4-octet field contains a bit map specifying the features of the neighbor switch. Bit assignments are as follows:
此4个八位组字段包含一个位图，用于指定相邻交换机的功能。位分配如下：
1 (unused) 2 The switch is a VLAN switch. 4 The switch has link state capability. 8 The switch has loop-free flood path capability. 16 The switch has resolve capability. 32 (unused) 64 The switch has tag-based flood capability. 128 The switch has tap capability. 256 The switch has message connection capability. 512 The switch has redundant access capability. 1024 The switch is an isolated switch. 4096 The switch is an uplink. (SFVLAN V1.8 only) 8192 The switch is an uplink to core. (SFVLAN V1.8 only) 16384 The port is an uplink port. (SFVLAN V1.8 only) 32768 The port is an uplink flood port. (SFVLAN V1.8 only)
1（未使用）2交换机是VLAN交换机。4交换机具有链路状态能力。8交换机具有无环路泛洪路径能力。16交换机具有解析能力。32（未使用）64交换机具有基于标签的泛洪功能。128开关具有抽头功能。256交换机具有消息连接功能。512交换机具有冗余访问能力。1024开关为隔离开关。4096交换机是上行链路。（仅限SFVLAN V1.8）8192交换机是到核心的上行链路。（仅限SFVLAN V1.8）16384该端口为上行端口。（仅限SFVLAN V1.8）32768该端口是上行链路泛洪端口。（仅限SFVLAN V1.8版）
Port number
端口号
This 4-octet field contains the logical number of the local port for which the event was generated.
此4-octet字段包含为其生成事件的本地端口的逻辑号。
Port neighbor switch identifier
端口邻居交换机标识符
This 10-octet field contains the internal identifier of the neighbor switch discovered on the port. The identifier consists of the 6-octet physical (MAC) address of the neighbor switch, followed by the 4-octet logical port number (local to the neighbor switch) on which the neighbor was discovered.
此10个八位字节字段包含在端口上发现的邻居交换机的内部标识符。该标识符由邻居交换机的6个八位字节物理（MAC）地址组成，后跟发现邻居的4个八位字节逻辑端口号（邻居交换机本地）。
Port neighbor IP address
端口邻居IP地址
This 4-octet field contains the Internet Protocol (IP) address of the neighbor switch.
此4-octet字段包含邻居交换机的Internet协议（IP）地址。
Neighbor chassis MAC address
邻居机箱MAC地址
This 6-octet field contains the physical (MAC) address of the chassis of the neighbor switch.
此6位字节字段包含相邻交换机机箱的物理（MAC）地址。
Neighbor chassis IP address
邻居机箱IP地址
This 4-octet field contains the Internet Protocol (IP) address of the chassis of the neighbor switch.
此4-octet字段包含邻居交换机机箱的Internet协议（IP）地址。
Neighbor functional level
邻域功能级
This 4-octet field contains the functional level of the neighbor switch, as determined by the version level of the SecureFast VLAN software under which this switch is operating. Valid values are as follows:
此4-octet字段包含邻居交换机的功能级别，由该交换机运行时使用的SecureFast VLAN软件的版本级别确定。有效值如下所示：
1 The switch is running a version of SFVLAN prior to Version 1.8. 2 The switch is running SFVLAN Version 1.8 or greater.
1交换机正在运行版本1.8之前的SFVLAN版本。2交换机正在运行SFVLAN版本1.8或更高版本。
Topology agent
拓扑代理
This 4-octet field contains a pointer to the topology agent that generated the event. The pointer here can reference any of the topology agents that send Interswitch Keepalive messages -- that is, any agent running the VlanHello protocol.
此4-octet字段包含指向生成事件的拓扑代理的指针。这里的指针可以引用发送交换机间Keepalive消息的任何拓扑代理，即运行VlanHello协议的任何代理。
Next event
下一个事件
This 4-octet field contains a pointer to the next event relay structure in the list.
此4-octet字段包含指向列表中下一个事件中继结构的指针。
The VlanHello protocol uses three timers.
VlanHello协议使用三个计时器。
o Send Hello timer. The Send Hello timer is used to control the interval at which Interswitch Keepalive messages are sent.
o 发送Hello定时器。发送Hello计时器用于控制交换机间Keepalive消息的发送间隔。
o Aging timer. The Aging Timer is used to detect when communication with a neighboring switch has been lost.
o 老化计时器。老化计时器用于检测与相邻交换机的通信何时中断。
o Going to Access timer. The Going to Access timer is used to synchronize the transition of a port state to Access and prevent a port from being prematurely designation as an Access port during network initialization. If an Unknown port receives any packet other than an Interswitch Keepalive message, the port state is set to Going To Access. If the switch receives an Interswitch Keepalive message over that port before the timer expires, the port state is changed to Network. Otherwise, when the timer expires, the port state is changed to Access.
o 正在访问计时器。进入访问计时器用于同步端口状态到访问的转换，并防止在网络初始化期间过早地将端口指定为访问端口。如果未知端口接收到除交换机间Keepalive消息以外的任何数据包，则端口状态设置为Gong to Access。如果交换机在计时器过期之前通过该端口接收到交换机间Keepalive消息，则端口状态将更改为Network（网络）。否则，当计时器过期时，端口状态将更改为Access。
The VlanHello protocol operates as part of the InterSwitch Message Protocol (ISMP) -- part of Cabletron's SecureFast VLAN (SFVLAN) product, as described in [IDsfvlan]. ISMP provides a consistent method of encapsulating and transmitting network control messages exchanged between SFVLAN switches.
VlanHello协议作为交换机间消息协议（ISMP）的一部分运行，ISMP是Cabletron的SecureFast VLAN（SFVLAN）产品的一部分，如[IDsfvlan]所述。ISMP提供了封装和传输SFVLAN交换机之间交换的网络控制消息的一致方法。
ISMP message packets are of variable length and have the following general structure:
ISMP消息包长度可变，一般结构如下：
o Frame header o ISMP packet header o ISMP message body
o 帧头o ISMP数据包头o ISMP消息体
ISMP packets are encapsulated within an IEEE 802-compliant frame using a standard header as shown below:
ISMP数据包使用标准报头封装在符合IEEE 802标准的帧内，如下所示：
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
00 | |
+ Destination address +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
04 | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Source address +
08 | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
12 | Type | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
16 | |
+ +
: :
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
00 | |
+ Destination address +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
04 | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Source address +
08 | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
12 | Type | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
16 | |
+ +
: :
Destination address
目的地址
This 6-octet field contains the Media Access Control (MAC) address of the multicast channel over which all switches in the fabric receive ISMP packets. The destination address fields of all ISMP packets contain a value of 01-00-1D-00-00-00.
此6-octet字段包含多播信道的媒体访问控制（MAC）地址，结构中的所有交换机通过该地址接收ISMP数据包。所有ISMP数据包的目标地址字段包含值01-00-1D-00-00-00。
Source address
源地址
This 6-octet field contains the physical (MAC) address of the switch originating the ISMP packet.
此6位字节字段包含发起ISMP数据包的交换机的物理（MAC）地址。
Type
类型
This 2-octet field identifies the type of data carried within the frame. The type field of ISMP packets contains the value 0x81FD.
此2个八位组字段标识帧内所携带的数据类型。ISMP数据包的类型字段包含值0x81FD。
The ISMP packet header consists of a variable number of octets, as shown below:
ISMP数据包头由可变数量的八位字节组成，如下所示：
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
00 |///////////////////////////////////////////////////////////////|
://////// Frame header /////////////////////////////////////////:
+//////// (14 octets) /////////+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
12 |///////////////////////////////| ISMP Version |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
16 | ISMP message type | Sequence number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
20 | Code length | |
+-+-+-+-+-+-+-+-+ +
| Authentication code |
: :
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
: :
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
00 |///////////////////////////////////////////////////////////////|
://////// Frame header /////////////////////////////////////////:
+//////// (14 octets) /////////+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
12 |///////////////////////////////| ISMP Version |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
16 | ISMP message type | Sequence number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
20 | Code length | |
+-+-+-+-+-+-+-+-+ +
| Authentication code |
: :
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
: :
Frame header
帧头
This 14-octet field contains the frame header.
此14个八位字节字段包含帧头。
ISMP Version
ISMP版本
This 2-octet field contains the version number of the InterSwitch Message Protocol to which this ISMP packet adheres. The VlanHello protocol uses ISMP Version 3.0.
此2-octet字段包含此ISMP数据包所遵循的交换机间消息协议的版本号。VlanHello协议使用ISMP版本3.0。
ISMP message type
ISMP消息类型
This 2-octet field contains a value indicating which type of ISMP message is contained within the message body. VlanHello Interswitch Keepalive messages have a message type of 2.
此2-octet字段包含一个值，该值指示消息正文中包含哪种类型的ISMP消息。VlanHello Interswitch Keepalive消息的消息类型为2。
Sequence number
序列号
This 2-octet field contains an internally generated sequence number used by the various protocol handlers for internal synchronization of messages.
此2-octet字段包含内部生成的序列号，由各种协议处理程序用于消息的内部同步。
Code length
代码长度
This 1-octet field contains the number of octets in the Authentication code field of the message.
此1个八位字节字段包含消息的身份验证代码字段中的八位字节数。
Authentication code
认证码
This variable-length field contains an encoded value used for authentication of the ISMP message.
此可变长度字段包含用于ISMP消息身份验证的编码值。
The ISMP message body is a variable-length field containing the actual data of the ISMP message. The length and content of this field are determined by the value found in the message type field.
ISMP消息正文是一个可变长度字段，包含ISMP消息的实际数据。此字段的长度和内容由消息类型字段中的值确定。
The format of the VlanHello Interswitch Keepalive message is described in the next section.
VlanHello Interswitch Keepalive消息的格式将在下一节中描述。
The VlanHello Interswitch Keepalive message consists of a variable number of octets, as shown below:
VlanHello Interswitch Keepalive消息由可变数量的八位字节组成，如下所示：
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
00 | |
+ Frame header / +
: ISMP packet header :
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
n | Version | Switch IP address ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
n+4 | ... Switch IP address | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
n+8 | |
+ Switch ID +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
n+16 | |
+ Chassis MAC address +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Chassis IP address ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
n+24 | ... Chassis IP address | Switch type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
n+28 | Functional level |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
n+32 | Options |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
n+36 | Base MAC count | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
n+40 | |
: Base MAC entries :
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
00 | |
+ Frame header / +
: ISMP packet header :
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
n | Version | Switch IP address ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
n+4 | ... Switch IP address | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
n+8 | |
+ Switch ID +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
n+16 | |
+ Chassis MAC address +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Chassis IP address ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
n+24 | ... Chassis IP address | Switch type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
n+28 | Functional level |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
n+32 | Options |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
n+36 | Base MAC count | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
n+40 | |
: Base MAC entries :
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
n = 21 + length of the authentication code of the packet
n=21+数据包认证码的长度
Frame header/ISMP packet header
帧报头/ISMP数据包报头
This variable-length field contains the frame header and the ISMP packet header.
此可变长度字段包含帧标头和ISMP数据包标头。
Version
版本
This 2-octet field contains the version number of the VlanHello protocol to which this message adheres. This document describes VlanHello Version 4.
此2-octet字段包含此消息所遵循的VlanHello协议的版本号。本文档描述了第4版。
Switch IP address
交换机IP地址
This 4-octet field contains the Internet Protocol (IP) address of the sending switch.
此4-octet字段包含发送交换机的Internet协议（IP）地址。
Switch ID
交换机ID
This 10-octet field contains the internal ISMP identifier of the sending switch. The identifier is generated by the sending switch and consists of the 6-octet physical (MAC) address of the switch, followed by a 4-octet value containing the logical port number over which the switch sent the packet.
此10个八位字节字段包含发送交换机的内部ISMP标识符。该标识符由发送交换机生成，由交换机的6位八位组物理（MAC）地址组成，后跟一个4位八位组值，其中包含交换机发送数据包的逻辑端口号。
Chassis MAC
机箱MAC
This 6-octet field contains the physical (MAC) address of the chassis of the sending switch.
此6位字节字段包含发送交换机机箱的物理（MAC）地址。
Chassis IP address
机箱IP地址
This 4-octet field contains the Internet Protocol (IP) address of the switch chassis.
此4-octet字段包含交换机机箱的Internet协议（IP）地址。
Switch type
开关类型
This 2-octet field contains the type of the switch. Currently, the only value recognized here is as follows:
此2-octet字段包含开关的类型。目前，此处识别的唯一值如下所示：
2 The switch is an SFVLAN switch.
2该交换机是一个SFVLAN交换机。
Functional level
功能级别
This 4-octet field contains the functional level of the sending switch, as determined by the version level of the SecureFast VLAN software under which this switch is operating. Valid values are as follows:
此4-octet字段包含发送交换机的功能级别，由该交换机运行时使用的SecureFast VLAN软件的版本级别确定。有效值如下所示：
1 The switch is running a version of SFVLAN prior to Version 1.8. 2 The switch is running SFVLAN Version 1.8 or greater.
1交换机正在运行版本1.8之前的SFVLAN版本。2交换机正在运行SFVLAN版本1.8或更高版本。
Options
选择权
This 4-octet field contains a bit map specifying the features of the switch. Bit assignments are as follows:
此4个八位字段包含一个位图，用于指定交换机的功能。位分配如下：
1 (unused) 2 The switch is a VLAN switch. 4 The switch has link state capability. 8 The switch has loop-free flood path capability. 16 The switch has resolve capability. 32 (unused) 64 The switch has tag-based flood capability. 128 The switch has tap capability. 256 The switch has message connection capability. 512 The switch has redundant access capability. 1024 The switch is an isolated switch. 4096 The switch is an uplink. (SFVLAN V1.8 only) 8192 The switch is an uplink to core. (SFVLAN V1.8 only) 16384 The port is an uplink port. (SFVLAN V1.8 only) 32768 The port is an uplink flood port. (SFVLAN V1.8 only)
1（未使用）2交换机是VLAN交换机。4交换机具有链路状态能力。8交换机具有无环路泛洪路径能力。16交换机具有解析能力。32（未使用）64交换机具有基于标签的泛洪功能。128开关具有抽头功能。256交换机具有消息连接功能。512交换机具有冗余访问能力。1024开关为隔离开关。4096交换机是上行链路。（仅限SFVLAN V1.8）8192交换机是到核心的上行链路。（仅限SFVLAN V1.8）16384该端口为上行端口。（仅限SFVLAN V1.8）32768该端口是上行链路泛洪端口。（仅限SFVLAN V1.8版）
Base MAC count
基本MAC计数
This 2-octet field contains the number of entries in the list of Base MAC entries.
此2-octet字段包含基本MAC条目列表中的条目数。
Base MAC entries
基本MAC条目
This variable-length field contains a list of entries for all neighboring switches that the sending switch has previously discovered on the port over which the message was sent. The number of entries is found in the Base MAC count field.
此可变长度字段包含发送交换机以前在发送消息的端口上发现的所有相邻交换机的条目列表。条目数位于基本MAC计数字段中。
Each MAC entry is 10 octets long, structured as follows:
每个MAC条目的长度为10个八位字节，结构如下：
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ Switch MAC address +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Assigned neighbor state ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... Assigned neighbor state |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ Switch MAC address +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Assigned neighbor state ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... Assigned neighbor state |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Switch MAC address
交换机MAC地址
This 6-octet field contains the base MAC address of the neighboring switch.
此6个八位字节字段包含相邻交换机的基本MAC地址。
Assigned neighbor state
指定的邻居国
This 4-octet field contains the assigned state of the neighboring switch as perceived by the sending switch. Currently, the only value valid here is 3, indicating a state of Network
此4个八位组字段包含发送交换机感知到的相邻交换机的分配状态。目前，这里唯一有效的值是3，表示网络状态
Security concerns are not addressed in this document.
本文件未涉及安全问题。
[RFC1700] Reynolds, J. and J. Postel, "Assigned Numbers", STD 2, RFC 1700, October 1994.
[RFC1700]Reynolds，J.和J.Postel，“分配的数字”，标准2，RFC 1700，1994年10月。
[IDsfvlan] Ruffen, D., Len, T. and J. Yanacek, "Cabletron's SecureFast VLAN Operational Model", RFC 2643, August 1999.
[IDsfvlan]Ruffen，D.，Len，T.和J.Yanacek，“Cabletron的SecureFast VLAN运营模型”，RFC 26431999年8月。
[IDvlsp] Kane, L., "Cabletron's VLS Protocol Specification", RFC 2642, August 1999.
[IDvlsp]Kane，L.，“Cabletron的VLS协议规范”，RFC 26421999年8月。
Dave Hamilton Cabletron Systems, Inc. Post Office Box 5005 Rochester, NH 03866-5005
Dave Hamilton Cabletron Systems，Inc.新罕布什尔州罗切斯特市邮政信箱5005号，邮编03866-5005
Phone:(603) 332-9400 EMail: daveh@ctron.com
电话：（603）332-9400电子邮件：daveh@ctron.com
Dave Ruffen Cabletron Systems, Inc. Post Office Box 5005 Rochester, NH 03866-5005
Dave Ruffen Cabletron Systems，Inc.新罕布什尔州罗切斯特市邮政信箱5005号，邮编03866-5005
Phone:(603) 332-9400 EMail: ruffen@ctron.com
电话：（603）332-9400电子邮件：ruffen@ctron.com
Copyright (C) The Internet Society (1999). All Rights Reserved.
版权所有（C）互联网协会（1999年）。版权所有。
This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English.
本文件及其译本可复制并提供给他人，对其进行评论或解释或协助其实施的衍生作品可全部或部分编制、复制、出版和分发，不受任何限制，前提是上述版权声明和本段包含在所有此类副本和衍生作品中。但是，不得以任何方式修改本文件本身，例如删除版权通知或对互联网协会或其他互联网组织的引用，除非出于制定互联网标准的需要，在这种情况下，必须遵循互联网标准过程中定义的版权程序，或根据需要将其翻译成英语以外的其他语言。
The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns.
上述授予的有限许可是永久性的，互联网协会或其继承人或受让人不会撤销。
This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
本文件和其中包含的信息是按“原样”提供的，互联网协会和互联网工程任务组否认所有明示或暗示的保证，包括但不限于任何保证，即使用本文中的信息不会侵犯任何权利，或对适销性或特定用途适用性的任何默示保证。
Acknowledgement
确认
Funding for the RFC Editor function is currently provided by the Internet Society.
RFC编辑功能的资金目前由互联网协会提供。