IPv6 CCNA Exploration version 4.0 Học viện mạng Cisco Bách Khoa - Website: www.ciscobachkhoa.com 2 Overview • IP version 6 (IPv6) was developed to overcome the limitations of the current standard, IP version 4 (IPv4). IPv4 allows end systems to communicate and forms the foundation of the Internet as we know it today. However, one of the major shortcomings of IPv4 is its limited amount of address space. The explosion of new IP-enabled devices and the growth of undeveloped regions have fueled the need for more addresses. • In the United States, the Department of Defense (DoD) is a primary driver for the adoption of IPv6. Học viện mạng Cisco Bách Khoa - Website: www.ciscobachkhoa.com 3 Introducing IPv6 • IP version 6 (IPv6) combines expanded addressing with a more efficient and feature-rich header to meet the demands for scalable networks in the future. • One key benefit is that IPv6 can recreate end-to-end communications without the need for Network Address Translation (NAT) • Cisco Systems currently supports IPv6 in Cisco IOS Software Release 12.2(2)T and later. Học viện mạng Cisco Bách Khoa - Website: www.ciscobachkhoa.com 4 IPv6 Features Học viện mạng Cisco Bách Khoa - Website: www.ciscobachkhoa.com 5 Large Address Space Học viện mạng Cisco Bách Khoa - Website: www.ciscobachkhoa.com 6 • IPv6 routers do not perform fragmentation. Instead, a discovery process determines the optimum maximum transmission unit (MTU) to use during a given session. • Link-layer technologies already perform checksum and error control. Because link-layer technologies are relatively reliable, an IP header checksum is considered to be redundant. Học viện mạng Cisco Bách Khoa - Website: www.ciscobachkhoa.com 7 Comparing IPv4 and IPv6 Headers • Flow Label: 20-bit field that allows a particular flow of traffic to be labeled. It can be used for multilayer switching techniques and faster packet-switching performance. • Extension Headers: Follows the previous eight fields. The number of extension headers is not fixed, so the total length of the extension header chain is variable. Traffic class: ToS Payload Length Next Header: Tcp, Udp… Hop Limit: TTL No Checksum Học viện mạng Cisco Bách Khoa - Website: www.ciscobachkhoa.com 8 Extension Header Extension Header Học viện mạng Cisco Bách Khoa - Website: www.ciscobachkhoa.com 9 IPv6 Extension Headers • IPv6 Header: Basic header described in the previous figure. • Hop-by-hop options header • Destination options header (when the routing header is used) • Routing header: Used for source routing and mobile IPv6 (value = 43). • Fragment header: Used when a source must fragment a packet that is larger than the MTU for the path between itself and a destination device. • Authentication header and Encapsulating Security Payload header: Used within IPsec to provide authentication, integrity, and confidentiality of a packet. The authentication header (value = 51) and the ESP header (value = 50) • Upper-layer header: Typical headers used inside a packet to transport the data. The two main transport protocols are TCP (value = 6) and UDP (value = 17). Học viện mạng Cisco Bách Khoa - Website: www.ciscobachkhoa.com 10 Defining Address Representation • Leading zeros in a field are optional, so 09C0 = 9C0 and 0000 = 0. • Successive fields of zeros can be represented as “::” only once in an address. • An unspecified address is written as “::” because it contains only zeros. [...]... 2003::1/64 ipv6 rip bkacad enable interface f0/0 ipv6 address 2fff::1/64 ipv6 rip bkacad enable interface s1/0 ipv6 address 2004::1/64 ipv6 rip bkacad enable ipv6 install netsh interface ipv6 add address "Local Area Connection" 2fff::2 2005::2/64 2004::2/64 R2 L0 ipv6 unicast-routing Ipv6 route ::/0 lo0 interface lo0 ipv6 address 2003::1/64 ipv6 rip bkacad enable interface f0/0 ipv6 address 2fff::1/64 ipv6. .. techniques to transition from IPv4 to IPv6 are as follows: – Dual stack – IPv6- over-IPv4 (6to4) tunnels For communication between IPv4 and IPv6 networks, IPv4 addresses can be encapsulated in IPv6 addresses Cisco IOS Dual Stack • Using IPv6 on a Cisco IOS router requires that you use the global configuration command ipv6 unicast-routing This command enables the forwarding of IPv6 datagrams • • • A dual-stack... similar to RIPv2 Uses IPv6 for transport IPv6 prefix, next-hop IPv6 address Uses the multicast group FF02::9, the all-RIP-routers multicast group, as the destination address for RIP updates Updates sent on UDP port 521 Command: – Router(config) #ipv6 router rip bkacad – Router(config-router)#maximum-paths 2 – Router(config)#interface fa0/0 – Router(config-if )ipv6 rip bkacad enable IPv6 to IPv4 Transition... end points of the tunnel, such as a firewall, filters out IPv4 protocol 41, which is the IPv6- over-IPv4 encapsulation Example of Configure 192.168.30.1 • The command that enables the IPv6 overlay tunnel is tunnel mode ipv6ip 6to4 tunneling • • • The 6to4 tunneling method automatically establishes the connection of IPv6 islands through an IPv4 network Each 6to4 site receives a /48 prefix, which is the... a /48 IPv6 prefix based on a single globally routable or reachable IPv4 address – Intra-Site Automatic Tunnel Addressing Protocol (ISATAP): Allows an IPv4 private intranet (which may or may not be using RFC 1918 addresses) to incrementally implement IPv6 nodes without upgrading the network LAB 2004::1/64 2003::1/64 L0 F0/0 2fff::1/64 2fff::2/64 R1 S1/0 S1/1 ipv6 unicast-routing interface lo0 ipv6 address... address A dual-stack node prefers IPv6 when available A new application programming interface (API) is defined to support both IPv4 and IPv6 addresses and Domain Name System (DNS) requests Past experience in porting IPv4 applications to IPv6 suggests that for most applications it is a minimal change in some localized places inside the source code Overlay Tunnels • • Tunneling IPv6 traffic over an IPv4 network... one edge router to encapsulate the IPv6 packet inside an IPv4 packet and another router to de-encapsulate it Tunneling is an integration method where an IPv6 packet is encapsulated within another protocol, such as IPv4 • • • • This method of encapsulation is IPv4 protocol 41 and has the following characteristics: Includes a 20-byte IPv4 header with no options and an IPv6 header and payload Considered... ipv6 unicast-routing Ipv6 route ::/0 lo0 interface lo0 ipv6 address 2003::1/64 ipv6 rip bkacad enable interface f0/0 ipv6 address 2fff::1/64 ipv6 rip bkacad enable interface s1/0 ipv6 address 2004::1/64 ipv6 rip bkacad enable ipv6 router rip bkacad redistribute static ... link-local prefix fe80::/64 is added -> fe80::00c:29ff:fec2:52ff Phase 3: Verify the address’s uniqueness on the link, called duplicate address detection (DAD) Send ICMPv6 Phase 4: Assigned IPv6 Multicast Address IPv6 Multicast Address • FF02::1:FFXX:XXXX — Solicited-node multicast on link, where XX:XXXX is the rightmost 24 bits of the corresponding unicast or anycast address of the node (Neighbor solicitation... has the following characteristics: Includes a 20-byte IPv4 header with no options and an IPv6 header and payload Considered dual stacking, which enables the connection of IPv6 islands without converting an intermediary network to IPv6 Tunneling presents these issues: – The MTU is decreased by 20 octets (if the IPv4 header does not contain any optional field) – Difficult to troubleshoot • • Encapsulation . driver for the adoption of IPv6. Học viện mạng Cisco Bách Khoa - Website: www.ciscobachkhoa.com 3 Introducing IPv6 • IP version 6 (IPv6) combines expanded. IPv6 CCNA Exploration version 4.0 Học viện mạng Cisco Bách Khoa - Website: www.ciscobachkhoa.com 2 Overview • IP version 6 (IPv6) was developed