Alphanumeric Strings - Cisco ASR 5000 Series Administration Manual

Alphanumeric Strings

CIDR notation is constructed from the IP address and the prefix size, the latter being the number of leading
1 bits of the routing prefix. The IP address is expressed according to the standards of IPv4 or IPv6. It is
followed by a separator character, the slash (/) character, and the prefix size expressed as a decimal number.
The address may denote a single, distinct, interface address or the beginning address of an entire network. In
the latter case the CIDR notation specifies the address block allocation of the network. The maximum size of
the network is given by the number of addresses that are possible with the remaining, least-significant bits
below the prefix. This is often called the host identifier.
For example:
• the address specification 192.168.100.1/24 represents the given IPv4 address and its associated routing
• the IPv4 block 192.168.0.0/22 represents the 1024 IPv4 addresses from 192.168.0.0 to 192.168.3.255.
• the IPv6 block 2001:DB8::/48 represents the IPv6 addresses from 2001:DB8:0:0:0:0:0:0 to
• ::1/128 represents the IPv6 loopback address. Its prefix size is 128, the size of the address itself, indicating
The number of addresses of a subnet defined by the mask or prefix can be calculated as 2
which the address size for IPv4 is 32 and for IPv6 is 128. For example, in IPv4, a mask of /29 gives 2
3
2 = 8 addresses.
Alphanumeric Strings
Some CLI commands require the entry of an alphanumeric string to define a value. The string is a contiguous
collection of alphanumeric characters with a defined minimum and maximum length (number of characters).
Character Set
The alphanumeric character set is a combination of alphabetic (Latin letters) and/or numeric (Arabic digits)
characters. The set consists of the numbers 0 to 9, letters A to Z (uppercase) and a to z (lowercase). The
underscore character ( _ ) and dash/hyphen (-) are also considered to be members of the alphanumeric set of
characters.
Blank spaces (whitespaces or SPACE characters) should mostly be avoided in alphanumeric strings, except
in certain ruledef formats, such as time/date stamps.
Do not use any of the following "special" characters in an alphanumeric string except as noted below:
• & (ampersand)
• ' (apostrophe)
• < > (arrow brackets) [see exception below]
• * (asterisk) [see wildcard exception below]
• { } (braces)
• [ ] (brackets)
• $ (dollar sign) [see wildcard exception below]
ASR 5500 System Administration Guide, StarOS Release 21.4
14
prefix 192.168.100.0, or equivalently, its subnet mask 255.255.255.0.
2001:DB8:0:FFFF:FFFF:FFFF:FFFF:FFFF.
that this facility consists of only this one address.
System Operation and Configuration
address size - mask
32-29
, in
=