IPv6 router warning (alert) Option

Summary

This article mainly describes an IPv6 hop-by-hop option type, which reminds the operation router (tansit router) to check the datagram content more carefully.

1. Introduction

New protocols, such as the use of control datagram by RSVP, include information that needs to be checked by the router (and sometimes need to be updated) When transmitting data to a specific address. We hope to transmit these packets as soon as possible, and to handle these special datagram as appropriate. However, the current situation is that, if the router needs to determine whether to check the content of the datagram, perform a syntax analysis on the upper-layer data content. The cost of this analysis is not small. We do not want this situation to happen again.

This article defines a new option. If this option exists in the datagram, the Router performs an in-depth check on the content of the datagram and updates the corresponding control data. If this item is not included in the datagram, the router does not have to worry about the check, as long as the route is enough. The host that implements IPv6 should be included in the implementation of this option.

2. Implementation Method

What we need to achieve is to provide a mechanism in which the router can process some data packets without checking each data packet. In the method described below, we define a new option in the IPv6 package, telling the router that this package needs to be checked and this option can be used by RSVP. This method does not cause more processing. If this option is not available in the datagram, the router does not check the datagram.

2.1 syntax

The format of the router warning option is as follows:

The first three bytes have 0 headers, And the number 5 of the other bits indicates the hop-by-hop option type number. If a host cannot recognize this option, it cannot be modified. Instead, it must process the following identified headers. The option domain content cannot be modified in the vro. We have noticed that there are two values after two bytes. The significance of this value is as follows:

0
Includes the datagram of a message that is detected by multicast listeners (Multicast listener disener ).

1
Datagram that includes the RSVP message

2
Datagram that includes active network messages

3-65535
Retained

2.2 Semantics

This option enables the vro to check the content of the datagram. Only protocols that use this option can check the content of the datagram according to the Protocol requirements. The target host of the datagram must ignore this option. If the value of this field cannot be recognized, it can only be ignored, and other fields in the Baotou can be processed. The router only needs to make a certain number of packetsProgramTo see what is interesting. This domain can be used in the implementation of vro operations. Note that the processing on the router may be outside the IPv6 layer, so the datagram must also be processed by UDP and RSVP. Once the datagram leaves the IP layer, it is difficult to define whether the router is an IP host or an IP router. To be accurate, the router processing is related to the domain value, but if necessary, the IP router should also process data like the IP host.

3. Impact on other Protocols

We must modify some protocols that require the router to process. If the datagram does not use the warning option, the router will not send data to these protocols. Finally, we should emphasize that this option must be included in RSVP messages.

4. Security

Excessive use of this option will cause the performance of the router to decline. If there is too much data in the datagram, or illegal requests will cause the router to crash. Therefore, some measures must be taken to protect the correct operation of the router. The measures are not discussed here.