Interface identifier

Q: How deeply does Acing the CCNA Exam: Volume 1 Fundamentals and Protocols cover interface identifier?

Explains address structure, three conversion steps, and Cisco configuration, but stops short of broader IPv6 address-assignment behavior.

As explained in Acing the CCNA Exam: Volume 1 Fundamentals and Protocols

An interface identifier is the 64-bit host portion of an IPv6 address that identifies a network interface within an IPv6 prefix.

An interface identifier is the 64-bit host portion of an IPv6 address. It identifies a network interface within an IPv6 /64 prefix. In a typical global unicast address, the first 48 bits are the global routing prefix, the next 16 bits identify a subnet, and the final 64 bits identify the interface. section 20.5.1

Modified EUI-64 automatically derives an interface identifier from a 48-bit MAC address:

Divide the MAC address into two 24-bit halves. section 20.4.2
Insert the reserved value fffe between the halves, producing 64 bits. section 20.4.2
Invert the seventh bit, represented by the third bit of the second hexadecimal digit. section 20.4.2

Cisco IOS configuration

Applying `ipv6 address 2001:db8:0:2::/64 eui-64` to R1 G0/2 lets IOS generate the interface identifier. For MAC address 0060.2f62.b803, the result is 0260:2fff:fe62:b803, producing 2001:db8:0:2:260:2fff:fe62:b803. The same identifier can appear in the interface's automatically generated link-local address. section 20.4.2

How Acing the CCNA Exam: Volume 1 Fundamentals and Protocols covers it

Cover of Acing the CCNA Exam: Volume 1 Fundamentals and Protocols

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Related concepts

IPv6produces · IPv6 is the sixth version of the Internet Protocol, using 128-bit network addresses for packet-based communication.
eui-64 keywordproduced by · The eui-64 keyword is a Cisco IOS interface-addressing keyword that requests automatic generation of an IPv6 interface identifier from the interface MAC address.
unique local addresspart of · A unique local address is an IPv6 private unicast address intended for use within internal networks and not for communication over the public internet.
global unicast addresspart of · A global unicast address is an IPv6 unicast address that is globally unique and routable over the internet.
link-local addresspart of · An IPv6 link-local address is an IPv6 unicast address valid only for communication between devices on the same local network segment.

This explainer was generated by Manning's knowledge graph from the text of Acing the CCNA Exam: Volume 1 Fundamentals and Protocols. The section links point to the parts of the book it draws on.