Physical Link Security Type of Service (RFC1455)
Original Publication Date: 1993-May-01
Included in the Prior Art Database: 2019-Feb-10
Internet Society Requests For Comment (RFCs)
This RFC documents an experimental protocol providing a Type of Service (TOS) to request maximum physical link security. This is an addition to the types of service enumerated in RFC 1349: Type of Service in the Internet Protocol Suite. This memo defines an Experimental Protocol for the Internet community.
Network Working Group D. Eastlake, III Request for Comments: 1455 Digital Equipment Corporation May 1993
Physical Link Security Type of Service
Status of this Memo
This memo defines an Experimental Protocol for the Internet community. Discussion and suggestions for improvement are requested. Please refer to the current edition of the "IAB Official Protocol Standards" for the standardization state and status of this protocol. Distribution of this memo is unlimited.
This RFC documents an experimental protocol providing a Type of Service (TOS) to request maximum physical link security. This is an addition to the types of service enumerated in RFC 1349: Type of Service in the Internet Protocol Suite. The new TOS requests the network to provide what protection it can against surreptitious observation by outside agents of traffic so labeled. The purpose is protection against traffic analysis and as an additional possible level of data confidentiality. This TOS is consistent with all other defined types of service for IP version 4 in that it is based on link level characteristics and will not provide any particular guaranteed level of service.
1. Nature of Requirement
This Internet Protocol addition addresses two potential security requirements: resistance to traffic analysis and confidentiality. These are described in the two subsections below followed by a discussion of why links have different levels of physical security so that it is meaningful to request that more secure links be used.
1.1 Traffic Analysis
At this time all Internet Protocol (IP) packets must have most of their header information, including the "from" and "to" addresses, in the clear. This is required for routers to properly handle the traffic even if a higher level protocol fully encrypts all bytes in the packet after the IP header. This renders even end-to-end encrypted IP packets subject to traffic analysis if the data stream can be observed. While traffic statistics are normally less sensitive than the data content of packets, in some cases activities of hosts or users are deducible from traffic information.
Eastlake [Page 1]
RFC 1455 Link Security TOS May 1993
It is essential that routers have access to header information, so it is hard to protect traffic statistics from an adversary with inside access to the network. However, use of more secure physical links will make traffic observation by entities outside of the network more difficult thus improving protection from traffic analysis.
No doubt users would like to be able to request a guaranteed level of link security, just as they would like to be able to request a guaranteed bandwidth or delay through the network. However, such guarantees require a resource reservation and/or policy routing scheme and are beyond the scope of the current IP Type of Service facility.
Although the TOS field is provided in all current Internet packets and routing based on TOS is provided in routing protocols such as OSPF [See 5,6,7]...