Filter
Top Products
ITG Engineering Guidelines Page 133 of
378
ITG Trunk 2.0 ISDN Signaling Link (ISL) Description, Installation and Operation
Private IP addresses
Private IP addresses are internal IP addresses that are not routed over the
Internet. They can be routed directly between separate intranets provided that
there are no duplicated subnets in the private IP addresses. Private IP
addresses can be used to set up the T-LAN and E-LAN, so that scarce public
IP addresses are used efficiently.
Three blocks of IP addresses have been reserved for private intranets:
• 10.0.0.0-10.255.255.255
• 172.16.0.0-172.31.255.255
• 192.168.0.0-192.168.255.255
Some routers and firewalls provide a Network Address Translation (NAT)
function that allows the customer to map a registered globally unique
public IP address to a private IP address without renumbering an existing
private IP address autonomous domain. NAT allows private IP addresses to
be accessed selectively over the Internet.
Public IP addresses
Public IP addresses can be used for the T-LAN and E-LAN, but will consume
limited resources.
This will have the same result as the private IP address solution, but the
E-LAN will be accessible from the Internet without NAT.
T-LAN engineering
The ITG nodes must be connected to the intranet so as to minimize the
number of router hops between the Meridian 1, provided there is adequate
bandwidth on the WAN links for the shorter route. This reduces the fixed and
variable IP packet delay, and improves the Voice over IP Quality of Service.
It is recommended that up to 4 cards (2 cards for Class B service) share the
same 10BaseT LAN broadcast collision domain, provided that the preferred
codec throughout the ITG network is set to G.729 Annex AB, G.729A, G.723
5.3K, or G.723 6.3K with 30 ms default payload size and default fax settings.
(In a passive Ethernet hub, all ports on the hub share one 10Mbit/s collision
domain for all connected MAC layer (Ethernet) addresses. In a switched
Ethernet hub, each port has its own collision domain.) Due to the much higher