Data and Voice Network Configuration

We are providing custom configuration of your Network / Router as per application requirement.

We provide services for different types of network protocol. We can configure DHCP to obtain ipaddress automatically, VLAN, ICMP, RIP, IGRP, NAT, Firewall, Voice Tunnel etc.

DCHP

A DHCP server maintains a database of available IP addresses and configuration information. When the server receives a request from a client, the DHCP server determines the network to which the DHCP client is connected, and then allocates an IP address or prefix that is appropriate for the client, and sends configuration information appropriate for that client. DHCP servers typically grant IP addresses to clients only for a limited interval. DHCP clients are responsible for renewing their IP address before that interval has expired, and must stop using the address once the interval has expired, if they have not been able to renew it

DHCP uses the concept of a "lease" or amount of time that a given IP address will be valid for a computer. The lease time can vary depending on how long a user is likely to require the Internet connection at a particular location. It's especially useful in education and other environments where users change frequently. Using very short leases, DHCP can dynamically reconfigure networks in which there are more computers than there are available IP addresses. The protocol also supports static addresses for computers that need a permanent IP address, such as Web servers.

DHCP is an extension of an earlier network IP management protocol, Bootstrap Protocol (BOOTP). DHCP is a more advanced protocol, but both configuration management protocols are commonly used and DHCP can handle BOOTP client requests. Some organizations use both protocols, but understanding how and when to use them in the same organization is important. Some operating systems, including Windows NT/2000, come with DHCP servers. A DHCP or BOOTP client is a program that is located in (and perhaps downloaded to) each computer so that it can be configured.

VLAN

Most of people already know what a LAN is but let's give it a definition to make sure. We have to do this because, if you don't know what a LAN is, you can't understand what a VLAN is.

A LAN is a local area network and is defined as all devices in the same broadcast domain. If you remember, routers stop broadcasts, switches just forward them.

A VLAN is a virtual LAN. In technical terms, a VLAN is a broadcast domain created by switches. Normally, it is a router creating that broadcast domain. With VLAN's, a switch can create the broadcast domain.

This works by, you, the administrator, putting some switch ports in a VLAN other than 1, the default VLAN. All ports in a single VLAN are in a single broadcast domain.

Because switches can talk to each other, some ports on switch A can be in VLAN 10 and other ports on switch B can be in VLAN 10. Broadcasts between these devices will not be seen on any other port in any other VLAN, other than 10. However, these devices can all communicate because they are on the same VLAN. Without additional configuration, they would not be able to communicate with any other devices, not in their VLAN.

ICMP

ICMP is actually a user of the IP protocol--in other words, ICMP messages must be encapsulated within IP packets. However, ICMP is implemented as part of the IP layer. So ICMP processing can be viewed as occurring parallel to, or as part of, IP processing. Therefore, in the topic on TCP/IP-based layered network, ICMP is shown as a layer 3 protocol.

ICMP is probably most well known as the message protocol used for the ping command. A ping command sends an ICMP echo request to the target host. The target host responds with an echo reply. The ping command is losing some of its usefulness in today's more security-conscious networks: many routers disable responses to echo requests.

RIP

RIP is a dynamic, distance vector routing protocol based around the Berkely BSD application routed and was developed for smaller IP based networks. RIP uses UDP port 520 for route updates. RIP calculates the best route based on hop count. Like all distance vector routing protocols, RIP takes some time to converge. While RIP requires less CPU power and RAM than some other routing protocols, RIP does have some limitations.

The RIP protocol in the form that we use now was developed in the 1970s at Xerox Labs as part of the XNS (Xerox Network Systems) Routing Protocol suite. The most popular variants are RIP version 1, described in RFC1058, and RIP version 2, described in RFC2453.

RIP version 2, or RIPv2 as it is more commonly known, was first proposed as an update to RIP in RFC1388 in January 1993. This RFC was later superseded by RFC1723 in November 1994 by Gary Scott Malkin and Scott Bradner. Neither of these RIPv2 proposals was intended to be a replacement for RIP, but they were both designed as an extension of RIP to provide additional functionality and capability. Some of these capabilities are compatible with RIP (first version) and some are not. To avoid supplying information to RIPv1 routes that could be misinterpreted, RIPv2 can use only noncompatible features when its packets are multicast. On interfaces that aren't capable of IP multicast, RIPv1-compatible packets that don't contain potentially confusing information are used. Some of the most notable RIPv2 enhancements are:

• Next hop
• Network mask
• Authentication
• RIP tag field

Firewall

In order for the 3CX Phone System to work with VoIP providers and directly connected external extensions it must be able to establish communication to the devices and VoIP providers and the firewall must be prepared to operate correctly with SIP.

A firewall without an integrated SIP server (AVM Fritz box or Speedport) or SIP ALG is preferable for use . The Microsoft ISA Server can not be used because it does not support static NAT.

The security of the internal network is still the responsibility of the System Administrator. The information gathered here describes only a technical implementation tailored to the 3CX Phone System. In general any open a port on the NAT router is a danger and must be protected by secure passwords, antivirus, and firewall updates.