From 8e7e5ce90ba23fbc26416d8e95ad1169af0b84d2 Mon Sep 17 00:00:00 2001 From: Othmar Gsenger Date: Fri, 27 Apr 2007 16:08:01 +0000 Subject: toc --- internet-draft-satp.html | 102 +++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 99 insertions(+), 3 deletions(-) (limited to 'internet-draft-satp.html') diff --git a/internet-draft-satp.html b/internet-draft-satp.html index f0b1b8a..2c49a5e 100644 --- a/internet-draft-satp.html +++ b/internet-draft-satp.html @@ -140,6 +140,7 @@ --> +

@@ -181,30 +182,96 @@ Copyright © The IETF Trust (2007).

The secure anycast tunneling protocol (satp) defines a protocol used for communication between any combination of unicast and anycast tunnel endpoints. It allows tunneling of every ETHER TYPE protocol (e.g. ethernet, ip, arp ...). SATP directly includes cryptography and message authentication based on the methodes used by SRTP. It is intended to deliver a generic, scaleable and secure solution for tunneling and relaying of packets of any protocol. +

+

Table of Contents

+

+1. +Introduction
+    1.1. +Notational Conventions
+2. +Motivation and usage scenarios
+    2.1. +Usage scenarions
+        2.1.1. +tunneling from unicast hosts over anycast routers to other unicast hosts
+        2.1.2. +tunneling from unicast hosts to anycast networks
+        2.1.3. +redundant tunnel connection of 2 networks
+    2.2. +Encapsulation
+3. +Using SATP on top of IP
+    3.1. +Fragmentation
+    3.2. +ICMP messages
+4. +Protocol specification
+    4.1. +Header format
+    4.2. +sender ID
+    4.3. +sequence number
+    4.4. +payload
+    4.5. +padding (OPTIONAL)
+    4.6. +padding count
+    4.7. +payload type field
+    4.8. +Encryption
+5. +Security Considerations
+    5.1. +Replay protection
+6. +IANA Considerations
+7. +References
+    7.1. +Normative References
+    7.2. +Informational References
+§ +Author's Address
+§ +Intellectual Property and Copyright Statements

+
+

+

Network Working Group	O. Gsenger
Internet-Draft	March 2007

1. Introduction

SATP is somehow a mixture of a generic encapsulation protocol like GRE (Farinacci, D., Li, T., Hanks, S., Meyer, D., and P. Traina, “Generic Routing Encapsulation (GRE),” March 2000.) [4] and a secure tunneling protocol as IPsec (Kent, S. and R. Atkinson, “Security Architecture for the Internet Protocol,” November 1998.) [5] in tunnel mode. To save some header overhead it uses the encryption technices of SRTP (Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. Norrman, “The Secure Real-time Transport Protocol (SRTP),” March 2004.) [1]. It supports peer to peer tunnels, where tunnel endpoints can be any combination of unicast, multicast or anycast hosts, so it defines a Host Anycast Service (Partridge, C., Mendez, T., and W. Milliken, “Host Anycasting Service,” November 1993.) [6]

+

1.1. Notational Conventions

The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC2119 (Bradner, S., “Key words for use in RFCs to Indicate Requirement Levels,” March 1997.) [2].

+

2. Motivation and usage scenarios

This section gives an overview of possible usage scenarios. Please note, that the protocols used in the figures are only examples and that SATP itself does not care about either transport protocols or encapsulated protocols. Routing is not done by SATP and each implemetation MAY choose it's own way of doing this task (e.g. using functions provided by the operating system). SATP is used only to encapsulate and encrypt data.

+

2.1. Usage scenarions

+

2.1.1. tunneling from unicast hosts over anycast routers to other unicast hosts

@@ -226,6 +293,7 @@ tunneling from unicast hosts over anycast routers to other unicast hosts

In this scenario the payload gets encapsuleted into a SATP packet by a unicast host and gets transmitted to one of the anycast routers. It than gets decapsulated by the router. This router makes a routing descision based on the underlying protocol and transmits a new SATP package to one or more unicast hosts depending on the routing descition.

+

2.1.2. tunneling from unicast hosts to anycast networks

@@ -254,6 +322,7 @@ tunneling from unicast hosts to anycast networks

When the unicast hosts wants to transmit data to one of the anycast DNS servers, it encapsulates the data and sends a SATP packet to the anycast address of the routers. The packet arrives at one of the routers, gets decapsulated and routed to the DNS server. This method can be used to tunnel between a clients and networks providing anycast services. It can also be used the other way to virtually locate a unicast service within anycasted networks.

+

2.1.3. redundant tunnel connection of 2 networks

@@ -277,6 +346,7 @@ redundant tunnel connection of 2 networks

Network A has multiple routers, that act as gateway/tunnel endpoints to another network B. This is done to build a redundant encrypted tunnel connection between the two networks. All tunnel endpoints of network A share the same anycast address and all tunnel endpoints of network B share another anycast address. When a packet from network A gets transmitted to network B, it first arrives on one of network A's border routers. Which router is used is determined by network A's internal routing. This router encapsulates the package and sends it to the anycast address of the network B routers. The SATP packet arrives at one of network B's routers and gets decapsulated and routed to it's destination within network B.

+

2.2. Encapsulation

@@ -321,10 +391,12 @@ Tunneling of IPv6 over IPv4 with RTP payload

Figure 4

+

3. Using SATP on top of IP

+

3.1. Fragmentation

@@ -335,16 +407,19 @@ Fragmentation

If the payload ip headers's Don't Fragment (DF) bit is set, than the DF bit of the outer ip header HAS TO be set as well.

+

3.2. ICMP messages

ICMP messages MUST be relayed according to rfc2003 section 4 (Perkins, C., “IP Encapsulation within IP,” October 1996.) [3]. This is needed for path MTU discover

+

4. Protocol specification

+

4.1. Header format

@@ -374,24 +449,28 @@ Header format

+

4.2. sender ID

The sender ID is a 16bit unsigned integer. It HAS TO be unique for every sender sharing the same anycast address

+

4.3. sequence number

The sequence number is a 32 bit unsigned integer in network byte order. It starts with a random value and is increased by 1 for every sent packet. After the maximum value, it starts over from 0. This overrun causes the ROC to be increased.

+

4.4. payload

A packet of the type payload type (e.g. an IP packet).

+

4.5. padding (OPTIONAL)

@@ -400,12 +479,14 @@ None of the pre-defined encryption transforms uses any padding; for these, the plaintext and encrypted payload sizes match exactly. Transforms are based on transforms of the SRTP protocol and these transforms might use the RTP padding format, so a RTP like padding is supported. If padding field is present, than the padding count field MUST be set to the padding lenght.

+

4.6. padding count

The number of octets of the padding field. This field is optional. It's presence is signaled by the key management and not by this protocol. If this field isn't present, the padding field MUST NOT be present as well.

+

4.7. payload type field

@@ -427,6 +508,7 @@ HEX

+

4.8. Encryption

@@ -461,23 +543,34 @@ Encryption

Figure 7

+

5. Security Considerations

As satp uses the same encrytion technics as SRTP (Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. Norrman, “The Secure Real-time Transport Protocol (SRTP),” March 2004.) [1], it shares the same security issues. This section will only discuss some small changes. Please read SRTP RFC3711 section 9 (Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. Norrman, “The Secure Real-time Transport Protocol (SRTP),” March 2004.) [1] for details.

+

5.1. Replay protection

Replay protection is done by a replay list. Every anycast receiver has it's own replay list, which SOULDN'T be syncronised, because of massive overhead. This leads to an additional possible attack. A attacker is able to replay a captured packet once to every anycast reciever. This attack is considered of be very unlikely, because multiple attack hosts in different loactions are needed to reach the seperate anycast receivers and the number of replays is limited to the count of receivers - 1. Such replays might also happen because of routing problems, so a payload protocol HAS TO be robust against a small number of duplicated packages. The window size and position HAS TO be syncronised between multible anycast receivers to limit this attack.

-

+

+

6. +IANA Considerations

+ +

To use the protocol on top of IP, UDP and TCP protocol numberes have to be +

+

+

+

7. References

-

6.1. Normative References

+

+

7.1. Normative References

@@ -488,7 +581,8 @@ References

[1]	Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. Norrman, “The Secure Real-time Transport Protocol (SRTP),” RFC 3711, March 2004.

-

6.2. Informational References

+

+

7.2. Informational References

@@ -499,6 +593,7 @@ References

[4]	Farinacci, D., Li, T., Hanks, S., Meyer, D., and P. Traina, “Generic Routing Encapsulation (GRE),” RFC 2784, March 2000.

+

Author's Address

@@ -517,6 +612,7 @@ References

http://www.gsenger.com/satp/

+

Full Copyright Statement

Copyright © The IETF Trust (2007).

-- cgit v1.2.3