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IPv6 技術理論與實務研習班 IPv6 Routing 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 22 Content Routing Basic Routing Protocols IPv6 Routing Concept RIPng for IPv6 Other IGP protocols for IPv6 Multiprotocols Extension for BGP-4 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 33 Content Routing Basic Routing Protocols IPv6 Routing Concept RIPng for IPv6 Other IGP protocols for IPv6 Multiprotocols Extension for BGP-4 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 44 Routing Routing is the network layer function Main issues in routing and flow control – – – – throughput average packet delay throughput = offered load – rejected load offered load may be rejected by the flow control mechanism 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網Offered 論 路 load 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 55 Delay requirement Flow Control Accepted traffic (throughput) Routing Packets Rejected load Network Performance Measured 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 66 The following examples illustrate the performance (delay) affected by the routing A good routing algorithm is to – – Increase throughput Decrease average delay 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 77 Example 1 5 units Paths (1, 3, 6) (2, 5, 6) are better than (1, 4, 6) and (2, 4, 6) 5 units 2 1 4 All links have A capacity of 10 units 5 3 6 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 88 Example 2 5 units 15 units 2 1 4 All links have A capacity of 10 units 5 3 6 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 99 Classifications of Routing Protocols Route change – static routing v.s. adaptive routing – – Static routing: the path used by the sessions of each origination-destination pair is fixed regardless of traffic condition. Adaptive routing: Paths change occasionally in response to congestion. 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 10 10 Routing and Flooding Flooding and broadcasting – – 不將收到之packet回送給來源端 不重覆送出相同之packet Shortest path routing – – Each communication link is assigned a positive number (called length), the length may be any measurement criteria Shortest path Min-hop (if the length of each link=1) 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 11 11 Introduction to Graph A Graph G is defined as (N, A), where N is a set of nodes, and a collection A of pairs of distinct nodes from N Spanning tree Minimum weight spanning tree 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 12 12 Importance of the Spanning tree A spanning tree is a subset of a network graph that includes all nodes There is only one path existed from the root node to each leaf node Reverse path forwarding Minimum Spanning tree 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 13 13 Considerations of Network Routing The length (weight) of each link (arc) may be measured by delay, cost, performance, … etc. Each node collects the network status (path information) to calculate the shortest path to destinations Each node shall broadcast its link information Flooding is necessary Each node decides the shortest path from its view point short path algorithms 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 14 14 Content Routing Basic Routing Protocols Overview IPv6 Routing Concept RIPng for IPv6 Other IGP protocols for IPv6 Multiprotocols Extension for BGP-4 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 15 15 IP Networks and Routing Interior Routing Protocols – – – RIP (Routing Information Protocol) OSPF (Open Shortest Path First) Other Protocols Exterior Routing Protocols – BGP (Border Gateway Protocol) 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 16 16 RIP RIP is a simple protocol based on distance vector Overview of distance vector routing – – – – Start up Link breaks Bouncing effect Counting to infinity Improvement schemes split horizon; triggered updates – Decrease the time to converge 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 17 17 Distance Vector D C B A Routing Table Routing Table Routing Table Routing Table Pass copies of routing table to neighbors periodically 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 18 18 Distance Vector 10.1.0.0 10.2.0.0 10.3.0.0 A B C Routing Table Routing Table Routing Table 10.1.0.0 0 10.2.0.0 0 10.3.0.0 0 10.2.0.0 0 10.3.0.0 0 10.4.0.0 0 10.3.0.0 1 10.4.0.0 1 10.2.0.0 1 10.4.0.0 2 10.1.0.0 1 10.1.0.0 2 •Routers build the best path to destinations based on information from each neighbor 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 19 19 Distance Vector Process to update this routing table B Process to update this routing table Router A sends out updated routing table A Topology change causes routing table update Updates proceed step-by-step from router to router 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 20 20 Comparison of RIPv1(rfc-1058, 1988) and RIPv2 (rfc-2453, 1998) Subnet routing – support subnet mask information Authentication – simple password protection defined in 2453, and MD5 is defined in rfc2082 Next hop indication Multicasting – define IP class D address for information advertisement. 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 21 21 OSPF distance vector routing – Link state routing protocols are based on the “distributed map” concept Changing information of the network is achieved by flooding protocol Main issue – to maintain a synchronized copy of the link state database in all nodes of the network secure map updates Shortest path first Dijkstra algorithm 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 22 22 Link-State Concept A2 A3 Link-State Packets A1 Topological Database Routing Table Dijkstra Algorithm Shortest Path First Tree After initial flood, only small event-triggered updates are passed to other routers 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 23 23 Distance Vector Routing v.s. Link-State Routing Distance Vector Link-State Views net topology from neighbor’s perspective Gets common view of entire network topology Adds hops from router to router Calculates the shortest path to other routers Frequent, periodic updates: slow convergence Event-triggered updates: faster convergence Passes copies of routing table to neighbor routers Passes link-state routing updates to other routers 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 24 24 Why is a link state protocol better? Fast, loopless convergency Support of precise/multiple metrics – The largest throughput; the lowest delay; the lowest cost; the best reliability; … Support multiple paths to a destination – Traffic splitting 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 25 25 Protocols within RIP and OSPF RIP – – – – RIP packets are carried over UDP/IP with port 520 Packets are sent every 30 seconds, or faster when triggered updates If a route is not refreshed within 180 seconds (6x30), the distance is set to infinity Each entry (one route) of RIP message is encoded over 20 bytes long (reservation part is used in RIPv2 for authentication, and etc.) 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 26 26 Protocols within RIP and OSPF OSPF – – OSPF runs on top of of the IP layer with protocol type 89 Composes of 3 subprotocols Hello: for checking the operation of the link and elect the designated/backup routers Exchange: master/slave operation for exchange the routing information in DB Flooding: to maintain the synchronization of the two databases 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 27 27 Other Routing Protocols Intermediate System to Intermediate System (IS-IS) – Defined by ISO in 1980s for DECnet (especially in the Backbone) and many concepts of IS-IS were adopted by OSPF IGRP (Internet Group Management Protocol) – – – Similar to ICMP and is a proprietary protocol defined by Cisco Distance vector family protocol Composite metrics: delay (D), bandwidth (B), reliability (R), load (L) 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 28 28 Choosing Routing Protocols Criteria – – convergence time Resource comsumption – – – IP address Network Bandwidth – link-state is better processing power and memory – distance-vector is better Ability to deal with multiple paths to a destination Scalability – link-state is better open standard or a proprietary protocol. 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 29 29 Choosing Routing Protocols Protocol RIP OSPF IGRP EIGRP Type distancevector linkstate distancevector distancevector Convergence Time slow fast slow fast VLSM no yes no yes Bandwidth Consumption high low high low Resource Consumption low high low low Multi-path Support no a yes yes yes Scales Well no yes yes yes Proprietary no no yes yes Routers Non-IP Protocols no no no yes a Some vendors may support multiple paths in RIP. 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 30 30 BGP Used for carrying routing information between AS’s Path vector protocol Runs over TCP (port 179) Conveys information about AS path topology AS 1 AS 2 BGP 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 31 31 AS-Path Topology AS 200 AS 100 170.10.0.0/16 180.10.0.0/16 180.10.0.0/16 300 200 100 170.10.0.0/16 300 200 AS 300 AS 400 150.10.0.0/16 AS 500 180.10.0.0/16 300 200 100 170.10.0.0/16 300 200 150.10.0.0/16 300 400 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 32 32 BGP4 RFC 1771 Intelligent route selection based on most specific prefix and shortest Autonomous System (AS) path BGP version 4 is the current de facto exterior routing protocol in the Internet BGP- 4 is required for CIDR 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 33 33 BGP BGP is run over TCP/IP (with port number 179) – TCP provides a reliable data transmission link (with fair flow/congestion control), however, – – – – Routing update packet to cure network congestion,… Security issue (rfc-2385, 1998 – Protection of BGP Sessions via TCP MD5 Signature Option”) Packet types of BGP OPEN UPDATE NOTIFICATION KEEPALIVE 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 34 34 BGP Initial exchange – – Use OPEN packet to check the BGP version and the “hold time” (the number of seconds used by the “keep alive procedure”) Use UPDATE packet to exchange (list of) “withdrawn routes” and metrics information of each path Updates – – Loop protection Stable – the path shall not oscillate too rapidly between reachable and unreachable 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 35 35 BGP Keep alive – According to the “hold time” value, and the keep alive messages will not exchanged for zero hold time. Error Notifications – – – – – – Message header error OPEN message error UPDATE message error Hold time expired Finite state machine error Cease (terminate the association) 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 36 36 Policy in BGP The commercial networks will not necessarily agree to freely relay third parties’ traffic Route decision process – Evaluate the paths that have been learned from external routers Attributes – – Describes the characteristics of a particular prefix AS path, Next hop, Local preference, Multi-exit discriminator (MED), …. 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 37 37 Content Routing Basic Routing Protocols Overview IPv6 Routing Concept RIPng for IPv6 Other IGP protocols for IPv6 Multiprotocols Extension for BGP-4 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 38 38 IPv6 Routing As in IPv4, IPv6 has two families of routing protocols: – – Interior Gateway Protocols (IGP) for inside autonomous systems Exterior Gateway Protocols (EGP) for peering between autonomous systems Same “longest-prefix match” routing as IPv4 CIDR Straightforward changes to existing IPv4 routing protocols to handle bigger addresses – unicast: OSPF, RIP-II, IS-IS, BGP4+, … – multicast: MOSPF, PIM, … 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 39 39 IPv6 Routing Concept The loopback address “0:0:0:0:0:0:0:1” is a virtual interface shall not send outside of a single interface. Link-local address – – Used on a single link for the purpose such as autoaddress configuration, neighbor discovery, or when no routers are present. Routers must not forward any packets with link-local source or destination address to other links. 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 40 40 IPv6 Routing Concept Link-local 10 54 64 1111111010 0 interface ID Site-local 10 1111111011 38 0 16 subbetID 64 interface ID 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 41 41 IPv6 Routing Concept Site-local address – – Used for addressing inside of a site without the need for global prefix. Routers must not forward ant packet with site-local source or destination address outside of the site. Global Site-Local Link-Local 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 42 42 Content Routing Basic Routing Protocols OverviewIPv6 Routing Concept RIPng for IPv6 Other IGP protocols for IPv6 Multiprotocols Extension for BGP-4 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 43 43 RIPng for IPv6 Based on RIPv2, supports split-horizon with poisoned reverse RFC2080 Most (if not all) IPv6 router implementations support RIP IPv6 Most IPv6-enabled Unix OS have the IPv6-RIP routed daemon available 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 44 44 RIPng for IPv6 Protocol Suite : Type : Application layer , interior gateway, distance vector Port : 521 ( UDP ) The destination prefix is the usual 128-bit , IPv6 address prefix stored as 16 octets in network byte order Packets are sent every 30 seconds , or faster when triggered updates 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 45 45 RIPng packet format Command(1) Version(1) Must be zero(2) Route Table Entry 1 (20) …… Route Table Entry N (20) 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 46 46 RIPng packet format Command : 8 bits Command 1 Request :A request for the responding system to send all or part of its routing table 2 Response:A message containing all or part of the sender’s routing table.This message may be sent in response to a request, or it may be an unsolicited routing update generated by the sender Version : 1 ; 8 bits 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 47 47 Response Messages A Response can be received for one of several different reasons: – response to specific query – regular update (unsolicited response) – triggered update caused by a route change 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 48 48 Route Table Entry(RTE) format IPv6 prefix (16) Route tag (2) IPv6 prefix : 16 bytes Route tag : 16 bits Prefix len : 8 bits Metric : 8 bits Prefix len (1) Metric (1) 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 49 49 The next hop RTE IPv6 next hop address (16) Must be zero (2) Must be zero(1) 0xFF 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 50 50 Timers and Split Horizon Two timers are associated with each route – – Timeout timer Garbage-collection time Split horizon – Split horizon is an algorithm for avoiding problems caused by including routes in updates sent to the nodes from which they were learned. 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 51 51 Content Routing Basic Routing Protocols Overview RIPng for IPv6 Other IGP protocols for IPv6 Multiprotocols Extension for BGP-4 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 52 52 OSPF for IPv6 Also known as OSPFv3 Important rewrite to remove IPv4 dependencies. (RFC 2470) protocol independent – – – – OSPFv3 runs over a link, rather than a subnet Link-local addresses are used Uses IPv6 for transport The important rewrite on the protocol has delayed the implementations. This results in an important delay for the deployment of IPv6 in large networks 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 53 53 IS-IS for IPv6 IS-IS is the OSI IGP protocol. It is network protocol independent Compared to OSPF, IS-IS for IPv6 is easier to implement and modify – new type-length-values (TLV) were defined: New protocol identifier for IPv6 Router vendors supporting IS-IS for IPv4 have or are probably going to have an IPv6 version – IPv6 Reachability (with 128 bits prefix) IPv6 Interface Address (with 128 bits) 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 54 54 Content Routing Basic Routing Protocols Overview RIPng for IPv6 Other IGP protocols for IPv6 Multiprotocols Extension for BGP-4 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 55 55 BGP4+ for IPv6 Includes multiprotocol extensions for BGP, for new address families (ex: IPv6, VPN, …) IPv6 address family: – – Use scoped addresses in the NEXT_HOP NEXT_HOP and NLRI are expressed as IPv6 addresses and prefix Most IPv6 router vendors support IPv6 BGP. It has been used on the 6Bone since 1996 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 56 56 Multiprotocol Extensions for BGP-4 It can carry routing information for multiple Network Layer protocol (e.g., IPv6 , IPX , etc…) The extensions are backward compatible – a router that supports the extensions can interoperate with a router that doesn’t support the extensions 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 57 57 Multiprotocol Extensions for BGP-4 To provide backward compatibility,as well as to simplify introduction of the multiprotocol capabilities into BGP-4; two new attributes are used: Multiprotocol Reachable NLRI (MP_REACH_NLRI) Multiprotocol Unreachable NLRI (MP_UNREACH_NLRI) 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 58 58 MP_REACH_NLRI (Type code 14) This is an optional non-transitive attribute that can be used for the following purposes: o o to advertise a feasible route to a peer to allow a given router to report some or all of the Subnetwork Points of Attachment (SNPAs) that exit within the local system MP_REACH_NLRI (Type code 14) Address Family Identifier ( 2 octets ) Subsequent Address Family Identifier ( 1 octet ) Length of Next Hop Network Address ( 1 octet ) Network Address of Next Hop ( variable ) Number of SNPAs ( 1 octet ) Length of first SNPA ( 1 octet ) First SNPA ( variable ) ……… Length of Last SNPA ( 1 octet ) Last SNPA ( variable ) Network Layer Reachability Information ( variable ) 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 60 60 MP_UNREACH_NLRI (Type Code 15 ) Address Family Identifier ( 2 octets ) Subsequent Address Family Identifier ( 1 octet ) Withdrawn Routes ( variable ) 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 61 61 Network Layer Reachability information(NLRI) encoding The Network Layer Reachability information is encoded as one or more 2-tuples of the form <length,prefix>,whose fields are described below: Length ( 1 octet ) Prefix ( variable ) 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 62 62 Network Layer Reachability information(NLRI) encoding The use and the meaning of these fields are as follows: Length: The Length in bits of the address prefix. A length of zero indicates a prefix that matches all (as specified by the address family) address (with prefix , itself , of zero octets) Prefix: The Prefix field contains address prefixes followed by enough trailing bits to make the end of the fall on an octet boundary 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 63 63 Subsequent Address Family Identifier 1 – Network Layer Reachability Information used for unicast forwarding 2 – Network Layer Reachability Information used for multicast forwarding 3 – Network Layer Reachability Information used for both unicast and multicast forwarding 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 64 64 Summary All routing protocols are available for IPv6 No real difference in the mechanics RIPv6 is based on RIP-2 OSPFv6 is a major rewrite IS-ISv6 includes few changes BGPv6 is based on Multiprotocol BGP 二 OO I p 二 v I p6 v 技 6 網 術 際 理 網 論 路 協 與 定 實 技 務 術 巡 研 迴 習 研 班 討 會 65 65