Summary
The Network record defines and groups address spaces, determines access to address spaces, assigns dynamic DHCP addresses and sets DHCP options. Generally, only Networking Systems and MedIT have access to Network records.
Fields
- Name
This name is actually used in DNS. The name must obey Internet naming standards and be unique within its domain. Under Internet naming standards, the name can contain only alphanumeric characters and the hyphen. No leading or trailing hyphens are allowed. The name must contain at least one letter.
- Location
These locations are where a computer can be plugged in, and be on this network.
- Groups
Users that are members of these Groups can modify this Network if they have Network record access.
- VLAN Area
VLAN numbers must be unique within a VLAN area, but can be reused in a different VLAN area. VLAN Area is not required, so it may be left empty, creating a "null," or default, VLAN area.
- VLAN Number
Unique, per VLAN area, number between 1 and 4094. To get the next available VLAN number in the current VLAN area click the Next Available button. To get the next available VLAN number greater than some number N, enter N into the VLAN Number field and click the Next Available button.
- Comment
Useful information of your own can be added here. It is searchable from the Full Search page. Only printable characters are valid for comments. The printable character set consists of the alphabet, any numbers, all punctuation and spaces. For example, the carriage return is a non-printable character.
- DHCP Service
Currently, there is only one possible selection, campus. In the future, different Networks may use different DHCP servers.
- DHCP Options
List desired DHCP options here. For more information, see DHCP options.
- Address Space
This section has several fields for each address space:
- Address Space
Address spaces are designated in "slash" format. For example, 171.64.20.0/24 designates an address space starting at 171.64.20.0 with a 171.64.20.128/25 Network prefix. Other acceptable input formats follow:
Input: Resolves to: 171.64.20/25 171.64.20/24 /24 171.64.20.0/24 - Low Reserve
Number of IP addresses at the bottom of the range that can only be assigned explicitly by a User with All Records access (i.e., gods). This number does not include the network address. For instance, if the low reserve is 2 in address space 171.64.20.0/24, the first assignable address by a regular User is 171.64.20.3. When creating an address space, the low reserve is set to 1 by default. This can be changed before saving.
- High Reserve
Number of IP addresses at the top of the range that can only be assigned explicitly by a User with All Records access (i.e., gods). This number does not include the broadcast address. For instance, if the high reserve is 3 in address space 171.64.20.0/25, the last assignable address by a regular User is 171.64.20.123. (171.64.20.127 is the broadcast, the addresses between the assignable address and the broadcast address are reserved). When creating an address space, the high reserve is set to 0 by default. This can be changed before saving.
- Prefix Box, Split and Join
These two (2) items are used only during modify operations. The prefix box specifies the new prefix to be used. The split/join specify the operation. A split or join cannot involve more than sixteen (16) address spaces. In other words, the new network prefix cannot be more than six (6) greater or less than than the old network prefix. For more on splitting and joining address spaces, please see below.
- Address Space Group
Users that are members of these Groups can assign IP addresses within this address space if they have Node record rights.
- Address Space DHCP Options
This is a list of DHCP options that apply to this address space. See DHCP Options for DHCP option list.
- Address Space Comment
Useful information can be added here. Searchable in Full Search.
- Dynamic DHCP Addresses
These addresses are used for roaming hosts (hosts with Roaming DHCP enabled). Each address is automatically assigned a name and is flagged active. These can be modified. See below for more about Dynamic DHCP addresses.
- Created By / Created Date
Person who created this record and the date it was created.
- Modified By / Modified Date
Person who last modified this record and the date of last modification
Actions on Address Spaces
Because of database limitations, some care must be taken when modifying address spaces. Unsaved address spaces cannot be split or joined because the results are unpredictable. To save an address space, hit the Save button for the entire Network.
The difference between the new and old network prefixes cannot be greater than six (6). That is to prevent operations like spitting a /8 Network into /29 Networks which severely affects performance of the NetDB system.
Note that any actions on address spaces do not affect existing address assignments.
- If adding first address range, type the address space in the box next to the checkbox. To add an additional address range, click on the "Add'l" button. Enter desired number of new address spaces in "Count" field if you want more than one. Type in the address range. The address space should be in w.x.y.z/n format where w.x.y.z is the network address and n is the network prefix.
- Enter a low and high reserve to prevent regular LNAs from assigning addresses at the bottom or top of the address range.
- Assign Groups - only Users in these Groups can assign addresses in this address space
- Click on DHCP Options to assign options to this address space. See DHCP Options for more information.
To delete an address space, uncheck the box next to the address space range. Save changes. Address spaces with addresses assigned to nodes cannot be deleted.
To move an address space,
- Go to the information page of the Network containing the address space.
- Click on "Move address space".
- Select the address space you want to move and what Network you want to move it to.
To split an address space, enter the new network prefix and click the "Split/Join" button.
To shrink an address space,
- Enter the new network prefix and click "Split/Join".
- Then remove the part of the address space that you no longer need by unchecking the box next to the address space range.
Expanding means making a bigger address space by adding unallocated address ranges to an existing address space. To expand an address space, enter in the new network prefix and click on "Split/Join". For example, if address space 171.64.20.0/24 is too small and 171.64.21.0/24 has not been allocated, one can expand the address space to 171.64.20.0/23.
Joining means making a bigger address space out of existing address spaces. To join or expand an address space, all the address ranges must exist in the same Network record. If the address spaces are distributed among several Networks, the address ranges must be moved into the same Network. For example, to join 171.64.20.0/25 and 171.64.20/24 into one Network, make sure both address spaces are on the same Network. Then enter "24" into the new network prefix box of either network prefix box and select "Split/Join". The page will return with the new address space. Save changes.
Dynamic DHCP addresses are handed out to roaming hosts and can only be added after address spaces are created.
- To add n addresses automatically, simply put n in the Count field, e.g., to add four (4) dynamic addresses automatically, simply put 4 in the Count field.
- To add a particular address, enter the address in the first box under "Dynamic DHCP addresses".
- Click on Save (saves entire Network) or Verify (which will reserve the addresses and display them) or Add'l (which will allow more dynamic addresses to be added).
- Dynamic DHCP address names are automatically generated from the IP address in this format: "dn<hex of IP address>". For instance, the name of dynamic address 171.64.3.5 171.64.3.5 would be "dnab400305". Once the address is saved, the name can be changed, but this is not generally recommended.
- Click on Save to save all changes.