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How many extension headers does IPv6 have?
IPv6 extension headers contains supplementary information used by network devices (such as routers, switches, and endpoint hosts) to decide how to direct or process an IPv6 packet. The length of each extension header is an integer multiple of 8 octets. This allows subsequent extension headers to use 8-octet structures.
What if the packet is IPv6 with no extension headers?
In a typical IPv6 packet, no extension headers are present. If special handling is required by either intermediate routers or the destination, the sending host adds one or more extension headers. Each extension header must fall on a 64-bit (8-byte) boundary.
What is IPv6 packet format?
An IPv6 packet has three parts: an IPv6 basic header, one or more IPv6 extension headers, and an upper-layer protocol data unit (PDU). An upper-layer PDU is composed of the upper-layer protocol header and its payload, which maybe an ICMPv6 packet, a TCP packet, or a UDP packet.
Which field determines the lifetime of IPv6 datagram?
Explanation: The Hop limit value is decremented by one by a router when the datagram is forwarded by the router. When the value becomes zero the datagram is discarded. The field is 8-bits wide, so an IPv6 packet can live up to 255 router hops only.
What is the minimum size of the IPv6 packet header?
The size of the IPv6 header has doubled from 20 bytes for a minimum-sized IPv4 header to 40 bytes. However, the new IPv6 header contains source and destination addresses that are four times longer than IPv4 source and destination addresses.
What is another name for IPv6 Mcq?
IPv6 (Internet Protocol version 6) is a set of specifications from the Internet Engineering Task Force (IETF) that is essentially an upgrade of IP version 4 (IPv4), a category of IP addresses in IPv4-based routing.
When did IPv6 start using packet headers?
Unlike IPv4, IPv6 has a formal mechanism for adding extension packet headers. This mechanism is specified in RFC 2460, “Internet Protocol, Version 6 (IPv6) Specification”, December 1998. RFC 2460 also specifies five extension headers:
Is there a maximum size for an IPv6 header?
The new extension header format allows IPv6 to be augmented to support future needs and capabilities. Unlike options in the IPv4 header, IPv6 extension headers have no maximum size and can expand to accommodate all the extension data needed for IPv6 communication.
Why do routers need an extension header for IPv6?
In these cases, a router must process the main header of the packet as well as the information in its payload. In the absence of extension headers, routers perform these functions on IPv6 traffic in the same way they do on IPv4 traffic, so the traffic can be forwarded in hardware.
When was the IPv6 Fragment header header specified?
This mechanism is specified in RFC 2460, “Internet Protocol, Version 6 (IPv6) Specification”, December 1998. RFC 2460 also specifies five extension headers: Of these, only the Fragment Header is really useful. Two additional Extension Headers were specified in RFC xxx, “IPsec”: