http://edge.networkworld.com/community/itaa/feed.xml ITAA RSS feed en http://edge.networkworld.com/community/itaa/frame-relay <p></p><p>I have Wendell's Official exam certification guide 2nd edition books and I haven't understood frame-relay DLCI yet. The first time I read about it I thought I had understood but after trying to make it work in packet tracer I got confused. First off I need you to check if my knowledge is correct. <span class='read-more'><a href="http://edge.networkworld.com/community/itaa/frame-relay"><br /><br /><strong>Read more</strong></a></span></p> http://edge.networkworld.com/community/itaa/frame-relay#comments The DLCI is a value assigned to each virtual circuit and DTE device connection point in the Frame Relay WAN. Two different connections can be assigned the same value within the same Frame Relay WAN—one on each side of the virtual connection. [<a href="http://www.cisco.com/en/US/docs/internetworking/technology/handbook/Frame-Relay.html">1</a>] So depending on whether your end is configured as DCE or DTE you may or may not need to assign the DLCI for your local interface. It sounds like your router was playing the DTE role and so after you assigned the DLCI you had both ends of the virtual circuit set up. <a href="http://www.dcbnet.com/notes/framerly.html">This page</a> provides a nice overview of frame relay to go with all the Cisco docs you're studying for the CCNA. Steve Cisco LANs / WANs Frame Relay Tue, 06 Jan 2009 09:20:38 -0500 36873 at http://edge.networkworld.com/community http://edge.networkworld.com/community/itaa/rommon-mode <p></p><p>What are the ways to avoid " rommon " mode such as the one given below ,after powering up a switch.</p> <p>########Console "Switch name" after power ON ############################</p> <p>0:00.569429: Please set IPAddr variable</p> <p>0:00.570013: Please set Netmask variable</p> <p>0:00.570368: Please set Broadcast variable</p> <p>0:00.570991: Please set TftpServer variable to do tftp downloads</p> <p>0:00.571542: Network is not configured</p> <p>WS-C2980G-A bootrom version 6.1(3), built on 2001.02.01 13:49:51</p> <p>H/W Revisions: Fin: 2 Dorsal: 7 Board: 1 <span class='read-more'><a href="http://edge.networkworld.com/community/itaa/rommon-mode"><br /><br /><strong>Read more</strong></a></span></p> http://edge.networkworld.com/community/itaa/rommon-mode#comments According to Cisco, "If a router keeps entering the ROM monitor mode each time the router is powered up or reloaded, the first setting that should be checked is the configured value of the configuration register." <a href="http://www.bradreese.com/cisco-rommon-recovery-procedures.htm">This page at www.bradreese.com</a> describes three reasons why a router or switch may go into ROM Monitor mode at boot time and provides direct links to Cisco documentation for recovery on a variety of hardware platforms. In a nutshell your device has lost its boot image and needs to have a new boot image loaded into the system using TFTP or possibly a flash memory card. To work with TFTP you will need a computer hosting TFTP server software that is reachable over the network from your device and you will probably need to connect a terminal to the console port as it is difficult if not impossible to load a new image via TFTP through a telnet connection. The Cisco release notes covering the WS-C2980G-A are available <a href="http://www.cisco.com/en/US/docs/switches/lan/catalyst4000/release/note/OL_4502.html">here</a> and contain information that may help you obtain a copy of the boot image you need if you do not have the software available. Hopefully all you need to do is issue a confreg command similar to >confreg 0x2102 in order to restore the boot mode and then restart to have it boot IOS properly. Steve Cisco LANs / WANs switches Mon, 05 Jan 2009 15:37:35 -0500 36843 at http://edge.networkworld.com/community http://edge.networkworld.com/community/itaa/computer-lab-network <p></p><p>What's the best possible way, also cheapest, to set up a network among 30 or so computers that will all be in the same room? What would I need, and how much would it all cost?</p> http://edge.networkworld.com/community/itaa/computer-lab-network#comments connect all the PCs to that. You can link from one of the ports on the switch into the network at the location you are at. Actually, there's an even cheaper solution: Find some used hubs in the 16-24 port range and hook a couple of them together. However, there's a cost to this cheapness: A slow network that will leave you and your users grumpy. With 30 computers, you probably want to think about management. I'd suggest spending a bit more and buying a manageable switch so that you can segment the computers into smaller networks - so if multiple groups are working on different projects, you can split them off into their own little worlds that shouldn't interfere with each other. As to cost, you could theoretically get by with spending a couple of hundred dollars. If you are a non-profit operation, you might be able to ask for donations of equipment from companies that are upgrading their equipment to newer versions to help reduce the cost even more. If you have to buy new, it could run a couple of thousand for a higher-end switch that will be manageable and come with other features that might prove helpful. These costs are in addition to the wiring you will need and a patch panel if you want the wiring to look nice without having patch cables running all over the place. Ron LANs / WANs SMB switches Mon, 29 Dec 2008 09:19:17 -0500 36690 at http://edge.networkworld.com/community http://edge.networkworld.com/community/itaa/vpn-setup <p></p><p>I have a VPN and I connect, but how can I connect as a static IP node on the network just as if I were there plugged in? I need other nodes to see me with a static IP address, just as if I were on-site. I connect to the VPN through my wireless router at home.</p> http://edge.networkworld.com/community/itaa/vpn-setup#comments Depending on the flavor of VPN client software and VPN system that you connect to at work, you could actually see more than one IP address locally. I don't how easy it will be to get a static IP for your remote workstations, however. Most of my experience for several years has been with Cisco VPN gear. In that respect, you can point the VPN unit you are terminating at (whether it be a PIX, ASA, VPN Concentrator, router, etc). You have an option at that point to either have the VPN device your connection terminates at to have it assign the IP address that your remote workstation will receive for the VPN connection or have a local DHCP server assign that address. You won't have an address out of the same IP subnet that the workstations on the local network have because the traffic for your connection has to be routed to get to you. What this could look like is that if you are using 10.1.10.0 /24 for a subnet at the main network location, your address for the remote connection would be from 10.1.11.0/24. Essentially you would have a local address, just not on the same subnet as some of the other users. If you have to be on the same subnet because of a legacy application requirement, you might be able to set up a NAT on the VPN device so that the address would appear out of the same subnet. The problem here is that you might have to do some interesting routing configurations so that for a specific IP address so that it would point to a different path to get the traffic to where you want it to be. I recently tried to help a reader with a Cisco setup do DHCP reservations so that they could get as close as you could try to a static address. In this case, the Cisco client generates what could be interpreted as a MAC address instead of using the hardware MAC address - it dynamically generates an address that doesn't seem to be the same every time a connection is established. It might be possible with open-source VPN clients or other vendors' VPN offerings to get an IP address out of the same pool that is being used locally or be able to always connect with the same static IP address, but I am not aware of any. This is where having the IP address being handed out by a local DHCP server at the company end of the VPN connection can help. By having it hand out the DHCP address, it should be able to coordinate that with the local DNS server so that local users will be able to find you by your machine name instead of having to get your IP address from you in order to be able to "see" you. Ron LANs / WANs Security SMB DHCP DNS VPNs Thu, 18 Dec 2008 11:22:15 -0500 36523 at http://edge.networkworld.com/community http://edge.networkworld.com/community/itaa/integration-data-networks-and-cellular-voice- <p></p><p>In terms of compatibility protocols and applications? For example: text messages from a computer to a mobile phone or vice versa, or e-mails from mobile phones to computers, etc.</p> http://edge.networkworld.com/community/itaa/integration-data-networks-and-cellular-voice-#comments Much of the integration you mention is available as standard features in today's cell phones and service plans. Sending text messages to mobile phones is typically as easy as sending e-mail to 123.456.7890@phonecompanygateway.com. Sending e-mail from phones is built in to most phones, even my ancient brick phone can send e-mail. Newer phones contain reasonably complete web browsers so there's less need to build custom implementations for mobile phone support than there used to be although there's a large number of mobile phone specific implementations being done. Much of that is for native applications running on the phone that will talk to the network directly without using a web browser to communicate with the remote server. Steve Wireless / Mobile Wed, 17 Dec 2008 11:13:12 -0500 36470 at http://edge.networkworld.com/community http://edge.networkworld.com/community/itaa/wireless-connection-problem <p></p><p>When I turn on my Dell Inspiron 8600 and the router is on, the computer keeps recycling, shuts itself down and starts back up and just keeps doing this. If I unplug the router, it comes up an works just fine. If I bypass the wireless router and plug in direct it works perfect. I know this sounds crazy but this is what's happening. Any help would be appreciated. </p> <p>Robert in Houston</p> http://edge.networkworld.com/community/itaa/wireless-connection-problem#comments Robert: From what you describe, it does sound like there is a problem between your laptop and the router. Here's what I'd try: 1) Download the latest network card drivers for your laptop. Although you work fine when plugged directly into the internet connection, it is possible that you might have a problem between the network card in the laptop and the router. 2) Go to the vendor's Web site, see if there is an updated firmware available and, if so, download it. If you are still having problems, try doing a hard reset of the router back to factory defaults and reconfigure it. There might be something in the router that is causing your laptop to reset when connected to it. The only way we might be able to find something out that would point us in the right direction would be to have a third laptop with <a href="http://www.cacetech.com/products/airpcap_family.htm">Cace Technologies AirPcap</a> adapter watching the wireless traffic to see if there is some type of command/signal coming from the access point that the laptop is interpreting as a reset/reboot command. See if you can borrow a friend's access point and duplicate the problem with that. If the problem goes away, it may be cheaper/easier to replace the access point/router than trying to figure out the problem. Ron SMB Wireless / Mobile Mon, 15 Dec 2008 09:45:26 -0500 36360 at http://edge.networkworld.com/community http://edge.networkworld.com/community/itaa/invalid-dns-server-address <p></p><p>What could be the reason(s) behind getting an invalid DNS Server Address in the <strong>Network Connection Detail Window</strong> in a Windows environment, even though the network behaves normally when the DNS Server addresses are mentioned statically?</p> http://edge.networkworld.com/community/itaa/invalid-dns-server-address#comments Perhaps you have a DHCP server handing out the wrong DNS server information when it grants your computer an IP address? It could happen if the DNS server address you are being given is being used by a machine with a DNS entry on the network, even if that machine is not running a DNS server. If the DNS server address you are picking up is not being used in the network and does not have a name associated with it then I would expect you would see many error messages in either the desktop event logs or the DHCP service logs if not both. Steve LANs / WANs DNS Wed, 10 Dec 2008 11:03:26 -0500 36220 at http://edge.networkworld.com/community http://edge.networkworld.com/community/itaa/only-half-available-bandwidth-can-be-used <p></p><p>I have a 10 Mbps/380 kbps ADSL line with two computers (one Vista and one XP) connected directly to the router and two more (again one Vista and one XP) connected through the wireless access point on the same router.</p> <p>I tested each of the computers individually, with other three turned off, and was able to establish he following: Vista computers achieve 8500/260 kbps, while XP computers get only about 4300/260 kbps. I tried switching cables and router connections, I also tried tweaking the Max MTU and RWIN values on the XP machines, but the result was still the same. <span class='read-more'><a href="http://edge.networkworld.com/community/itaa/only-half-available-bandwidth-can-be-used"><br /><br /><strong>Read more</strong></a></span></p> http://edge.networkworld.com/community/itaa/only-half-available-bandwidth-can-be-used#comments Vista's TCP/IP networking stack is considerably improved over XP's. <a href="http://www.nanog.org/mtg-0610/presenter-pdfs/gbadegesin.pdf">This NANOG presentation</a> delivered by Microsoft provides an overview of the evolution of the networking code and describes a number of the improvements made to Vista compared to XP. The biggest contributer to the performance difference you describe seeing apparently results from Vista's self-tuning capabilities that will modify the receive window size and other parameters dynamically to improve throughput. Vista also takes advantage of the "window scale" option which XP does not use at all. The window scale option allows the system to use much larger window sizes can speed up transfers significantly. If you are interested in more detail about the differences in Vista's TCP/IP stack you may find <a href="http://technet.microsoft.com/en-us/library/bb878108.aspx">this Microsoft Technet article</a> and <a href="http://www.geekzone.co.nz/juha/2070">this geekzone discussion</a> helpful. Steve LANs / WANs Microsoft operating systems Vista Windows Windows XP Mon, 08 Dec 2008 10:24:08 -0500 36124 at http://edge.networkworld.com/community http://edge.networkworld.com/community/itaa/wireless-connection <p></p><p>Signal strength shows "excellent", but it's still limited or no connectivity in my status window.</p> http://edge.networkworld.com/community/itaa/wireless-connection#comments The limited or no connectivity message makes it sound like you are not getting an IP address from the wireless network in order to connect. The first thing to try is "Repair"ing your wireless connection. Right click the wireless adapter icon in the network control panel and choose Repair. If that doesn't work then it could be that you are being blocked by security settings from even connecting to obtain an IP address. Is the wireless access point device (router?) distributing IP addresses using DHCP? Does your computer obtain an IP address? Do you have wireless security enabled at the wireless access point? Typically the symptoms you describe are the result of a forgotten password or mismatched security or wireless protocol settings (b,g,n...) between the computer wireless adapter and the wireless router or access point. Go back to square one. Turn everything off. Reboot. Reset all the security settings so that the wireless network is running with no access control. Make sure the wireless adapter on the computer and the wireless access point or router are configured to use the same wireless band and try to connect. If that fails and your router has an option for changing "channels" then try a different channel. If you are using the Windows wireless configuration utility, switch to using the wireless adapter vendor's configuration utility and try again. Another recommendation is to make sure that your computer has the most recent BIOS software. Steve Wireless / Mobile Fri, 05 Dec 2008 09:41:36 -0500 36052 at http://edge.networkworld.com/community http://edge.networkworld.com/community/itaa/how-get-one-printer-work-either-two-computers <p></p><p>Situation: one home computer and one printer in one room, connected by a cable thru a router. Another computer in another room, connected wirelessly through the same router. I want to be able to print from either computer. The computer/printer combo (in the same room) works. The computer in the other room won't print. I don't know the correct setup for the other computer. Recommendations, please.</p> http://edge.networkworld.com/community/itaa/how-get-one-printer-work-either-two-computers#comments You say the hard wired computer is connected to the printer by a cable though the router so I am assuming this is a network printer. One way to print from the wireless computer is to share the printer from the computer that is hard wired so that the wireless computer can print to the printer by using the shared printer on the hard wired computer. To share the printer on a windows machine you highlight the printer in the printer list, right-click to bring up the menu, choose Properties, select the Sharing tab, and choose the "Share this Printer" option. After that you can connect from the wireless computer to the hard wired computer and select the shared printer and print a test page. After that you should be able to use the printer at will. Another way to print is directly to the network printer, but first you need to make sure that your router will pass wireless traffic on the port number used by the printer over to the printer and then you can set the wireless computer up the same way the hard wired computer is set up to print to the printer. If the printer has an IP address assigned you can use the ping command to verify that your wireless computer can connect to the printer. If you can not seem to make the connection to the printer you may need to review the instructions for your router and make some changes to the settings to enable network traffic to reach the printer from the wireless computer. Steve SMB Wireless / Mobile printers Thu, 04 Dec 2008 10:25:03 -0500 36012 at http://edge.networkworld.com/community