Ch 3 IPV6 Addressing - EDITED.pptx

Chapter 3: Internet Protocol Version (IPv6)  Chapter 8 Objectives The CCENT Topics Covered in this chapter include: IP addressing (IPv4 / IPv6) Identify the appropriate IPv6 addressing scheme to satisfy addressing requirements in a LAN/WAN environment Describe the technologic...

Chapter 3: Internet Protocol Version (IPv6)  Chapter 8 Objectives The CCENT Topics Covered in this chapter include: IP addressing (IPv4 / IPv6) Identify the appropriate IPv6 addressing scheme to satisfy addressing requirements in a LAN/WAN environment Describe the technological requirements for running IPv6 in conjunction with IPv4 such as dual stack Describe IPv6 addresses  Global unicast  Multicast  Link local  Unique local  eui 64  autoconfiguration IP Routing Technologies  Configure and verify OSPF (single area)  Configure OSPF v3 2 Why Transition to IPv6? Communication Limits: Current IPv4 system can't keep up with global communication demands. Bandwidth and IP Conservation: Efforts to save IPv4 addresses, like using VLSMs, are stopgap measures. Address Exhaustion: IPv4 offers about 4.3 billion addresses, which are nearly depleted despite techniques like CIDR and NAT. Growing Online Population: Emerging markets, such as China, are adding vast numbers of users who need IP addresses. History of IP Protocols in IPv6 OSPF (Open Shortest Path First) Version 2: Utilized with IPv4 for routing. Upgrade to Version 3: Enhanced to support IPv6 addressing and features. ICMP (Internet Control Message Protocol) Original ICMP: Integral part of IPv4 for error messages and operational information. Upgrade to ICMPv6: Expanded to handle IPv6 operations, including error reporting and diagnostic functions. ARP (Address Resolution Protocol) ARP with IPv4: Translates IP addresses to MAC (Media Access Control) addresses. Replaced by NDP (Neighbor Discovery Protocol) with IPv6: Performs the function of ARP plus several additional features to efficiently manage neighbor discovery and reachability in IPv6 networks. Understanding IPv6 Routing IPv6 Address Requirement: End-user devices must have an IPv6 address assigned to their interface to initiate IPv6 packet creation and transmission. Default Router Knowledge: Devices need to know the IPv6 address of a default router. This is the router to which the device sends all IPv6 packets not destined for the local subnet. Understanding IPv6 Routing Packet Handling by Routers: IPv6 routers process packets by removing (de- encapsulating) and adding (re-encapsulating) packet headers as they move packets between different network segments. Routing Decisions: Routers determine the path for each IPv6 packet based on a comparison between the packet's destination address and the entries in the router's IPv6 routing table. The routing table provides the next hop towards the packet's final destination.  IPv6 address example Global Prefix: The network portion provided by the ISP. Subnet: Defines subnetworks within an organization. Interface ID: Unique to each device on the network. Expanded Size: IPv6 addresses have eight groups of hexadecimal numbers compared to IPv4's four groups of decimal numbers. Hexadecimal Notation: Unlike IPv4's numerical values, IPv6 uses hexadecimal (including letters), which allows for a much larger address space. Delimiter Change: Groups in IPv6 are separated by colons (:), not periods (.), emphasizing the difference in structure and notation. 16-Bit Blocks: Each of the eight groups represents a 16-bit block in  IPv6 address example The size of an IPv6 address is 128 bits, compared to 32 bits in IPv4. The address space therefore has =340,282,366,920,938,463,463,374,607,431, 768,211,456 addresses  Shortened Expression to reduce IPv6 size The good news is there are a few tricks to help rescue us when writing these long addresses. Zero Compression: Use ‘::’ to represent one or more groups of zero. Single Occurrence: The ‘::’ can only appear once in an IPv6 address to avoid ambiguity. Example 1: 2001:db8:3c4d:12:0:0:1234:56ab We can remove one or more consecutive blocks of zeros by replacing them with a doubled colon ‘::’, like this: 2001:db8:3c4d:12::1234:56ab Example 2: 2001:0000:0000:0012:0000:0000:1234:56ab And just know that you can’t do this: 2001::12::1234:56ab Instead, the best you can do is this: 2001::12:0:0:1234:56ab Examples-Exercise Answers  Address Types Unicast: Definition: Delivered to a single interface. Load Balancing Exception: Multiple interfaces may use the same unicast address for anycast purposes. Global Unicast Addresses (2000::/3): Publicly Routable: Similar to public IPv4 addresses. ISP Allocation: ISPs typically provide a /48 network ID, allowing for a unique 64-bit interface address. Structure: Consists of a network ID and a unique host ID. Link-Local Addresses (FE80::/10): Non-Routable: Used for local communications on a single network segment. Comparison: Analogous to IPv4's APIPA, they start with FE80. Purpose: Not intended to be routed beyond a single network link.  Address Types Continuous…. Unique Local Addresses (FC00::/7): Private Communication: Equivalent to IPv4's private addresses. Usage: Enables site-wide communication, routable across multiple internal networks. Multicast (FF00::/8): One-to-Many: Packets are delivered to all interfaces listening to the multicast address. Recognition: Always begin with 'FF’. Anycast: One-to-Nearest: Packets are delivered to the closest interface in terms of routing distance. Special IPv6 addresses IPv6 global unicast addresses  Manual Address Assignment Enable IPv6 Traffic Forwarding: Use global configuration command to enable IPv6 on a router. Command: ipv6 unicast-routing By default, IPv6 is not forwarded until this command is applied. Assign IPv6 Address to Interface: Use interface configuration command to manually assign an IPv6 address. Command: ipv6 address / Example: ipv6 address 2001:db8:3c4d:1:0260:d6FF.FE73:1987/64 Using EUI-64 for Interface ID: Leverages the device's MAC address for automatic Interface ID creation. Command: ipv6 address 2001:db8:3c4d:1::/64 eui-64 EUI-64 pads the MAC address to create a unique 64-bit interface identifier.  Stateless EUI-64 interfaceAutconfiguration IDassignment Autoconfiguration is an especially useful solution because it allows devices on a network to address themselves with a link-local unicast address as well as with a global unicast address. Let’s say I have a device with a MAC address that looks like this: 0060:d673:1987. After it’s been padded, it would look like this: 0260:d6FF:FE73:1987. So where did that 2 in the beginning of the address come from? Two Steps to IPv6 autoconfiguration  IPv6 autoconfiguration example Branch router needs to be configured, without typing in an IPv6 address on the interface connecting to the Corp router. Also, without typing in any routing commands, but I need more than a link-local address on that interface. So basically, I want to have the Branch router work with IPv6 on the internetwork with the least amount of effort. Using the command ipv6 address autoconfig, the interface will listen for RAs and then, via the EUI-64 format, it will assign itself a global address  DHCPv6 (Stateful Configuration) Router Solicitation (RS) & Advertisement (RA) Initial Process: Devices on the network first listen for Router Advertisements (RA) to get prefix information. DHCPv6 Server Discovery: The RA message indicates if DHCPv6 is available. If no router is found, the client sends a DHCPv6 Solicit message. DHCPv6 Solicit Message: This is a multicast message sent by the client. It has a destination address of ff02::1:2. The message requests DHCP servers and relay agents to respond.  IPv6 header When IPv6 designers devised the header, they created fewer, streamlined fields that would also result in a faster routed protocol at the same time.  IPv6 header Version This 4-bit field contains the number 6, instead of the number 4 as in IPv4. Traffic Class This 8-bit field is like the Type of Service (ToS) field in IPv4. Flow Label This new field, which is 24 bits long, is used to mark packets and traffic flows. A flow is a sequence of packets from a single source to a single destination host, an anycast or multicast address. The field enables efficient IPv6  IPv6 header Payload Length IPv4 had a total length field delimiting the length of the packet. IPv6’s payload length describes the length of the payload only. Next Header Since there are optional extension headers with IPv6, this field defines the next header to be read. Hop Limit This field specifies the maximum number of hops that an IPv6 packet can traverse. Source Address This field of 16 bytes or 128 bits identifies the source of the packet. Destination Address This field of 16 bytes or 128 bits identifies the destination of the packet.  ICMPv6 Acts as an extension to the basic IPv6 header. Identified by the number '58' in the 'Next Header' field of the IPv6 packet. Uses of ICMPv6: Facilitates messages for network operation such as router and neighbor discovery. Utilized for Router/Neighbor Solicitation and Advertisement. Neighbor Discovery Protocol (NDP): Works like ARP in IPv4 but is part of ICMPv6. Discovers the link-layer addresses (MAC addresses) of other local devices. NDP Functions: MAC Address Resolution: Determines MAC addresses of neighbors. Router Solicitation (RS): Sent to FF02::2 to find routers. Router Advertisement (RA): Routers announce presence via FF02::1.  ICMPv6 Figure shows how ICMPv6 has evolved to become part of the IPv6 packet itself.  ICMPv6 Type Field: Specifies the ICMPv6 message type, determining the packet's purpose (e.g., error reporting or informational message). Code Field: Provides further granularity/details about the message type. Data Field: Contains the ICMPv6 message payload. Router solicitation (RS) and router advertisement (RA) IPv6 hosts send a router solicitation (RS) onto their data link asking for all routers to respond, and they use the multicast address FF02::2 to achieve this. Routers on the same link respond with a unicast to the requesting host, or with a router advertisement (RA)  IPv6 static and default routing Purpose: The static route on Corp guides traffic to a specific network. The default route on Branch handles all other destinations. Static Route on Corp Router: A specific route to network 2001:1234:4321:1::/64 is configured. Uses a specified next-hop IPv6 address or the router's exit interface. Default Route on Branch Router: A default route ::/0 is set up for all unspecified traffic. Directs traffic through the Branch router's GigabitEthernet interface  OSPFv3 It is a link state routing protocol that divides an entire internetwork or AS into areas, creating a hierarchy. In OSPF version 2, the router ID (RID) is determined by either the highest IP addresses assigned to the router or one you manually assigned. In version 3, you assign the RID and area ID, which are both still 32-bit values. Adjacencies and next-hop attributes now use link-local addresses. OSPFv3 still uses multicast traffic to send its updates and acknowledgments, with the addresses FF02::5 OSPF routers and FF02::6 for OSPF-designated routers as replacements for OSPV2 224.0.0.5/6 addresses. To enable IPv6 routing, use command: Corp(config)#ipv6 unicast-routing OSPF Commands, Enter OSPFv3 router configuration : #ipv6 router osfp 10 Assign router ID: #router-id 1.1.1.1 Link OSPFv3 to an interface and area: #ipv6 ospf 10 area 0  Written Labs and Review Questions Read through the Exam Essentials section together in class Open your books and go through all the written labs and the review questions. Review the answers in class. 31