Verizon DSL Lags, Verizon says everything OK, Right!
I'm the administrator for a workgroup of 25 computers in a 2 story office. Since the 1st of the year we've had a problem with Verizon DSL. It lags. We run a Netgear FVS124G two WAN port router. The Primary port is connected to Verizon DSL via a Westell 327W modem connected to a Verizon telephone line. The secondary port is connected to a Velocity Network DSL via Netopia 4541 modem connected to a second Verizon telephone line. The problem is that at random times and with random traffic loads, the response time for loading webpages is slow. Sometimes, it will load OK (not great), someitmes it will load partially and then sttall. Reload then loads the rest of the page OK. Sometimes, it won't load at all. We have replaced the router and modems without any difference. We reboot the modem and it works fine for a few minutes and then back to its old, slow ways. Verizon and Velocity both keep saying the line is fine and won't send anyone out to look at the wiring between the office and the CO. The closest anyone has come to admitting there is a problem is that a tech found log entries for the lines that include aboout a dozen errors within an 8 hour preiod, "Code Violation" and "Forwarding Error Corrrection". Any Sugestions as to what to do from here? Thank you for any and all help.
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The Modems we have including the replacements have all come from the ISPs. The router is ours. And is the latest vwersion of the Netgear FVS124G. The ISPs have both said nothing about the router.
A couple of things I'd try:
1) You don't seem to have a sense for whether it's one or both connections that are running slow. I'd suggest disconnecting one, then the other, to see whether the problem is localized to one connection.
2) Once you know which connection is responsible (one or both), try putting a single computer directly on that DSL modem and using it. Do you still get the same results, or does it operate at what should be normal speeds? Often, ISP service departments find it easier to troubleshoot a problem when it's happening with a computer directly linked to their line, as there are no LAN issues to worry about.
3) Have you checked the router's status page to see how much activity there is? It's possible that one of your computers has been infected by rogue software that's eating up all your bandwidth. Your router status page has a "Show Statistics" button that displays transmitted and received packets and bytes; make sure the numbers are reasonable. (You might want to check this after hours, when there should be minimal legitimate activity.) If you don't have a copy of the router's manual available, you can get one online at http://kbserver.netgear.com/pdf/FVS124G_RM_30Mar05.pdf
1) You don't seem to have a sense for whether it's one or both connections that are running slow. I'd suggest disconnecting one, then the other, to see whether the problem is localized to one connection.
2) Once you know which connection is responsible (one or both), try putting a single computer directly on that DSL modem and using it. Do you still get the same results, or does it operate at what should be normal speeds? Often, ISP service departments find it easier to troubleshoot a problem when it's happening with a computer directly linked to their line, as there are no LAN issues to worry about.
3) Have you checked the router's status page to see how much activity there is? It's possible that one of your computers has been infected by rogue software that's eating up all your bandwidth. Your router status page has a "Show Statistics" button that displays transmitted and received packets and bytes; make sure the numbers are reasonable. (You might want to check this after hours, when there should be minimal legitimate activity.) If you don't have a copy of the router's manual available, you can get one online at http://kbserver.netgear.com/pdf/FVS124G_RM_30Mar05.pdf
I think what I mean is do'nt take no for an answer - it sounds likes kids at the other end and not experts - make a point of putting the problem back onto them and get them to get the confgiguratino of your circuit -they have the ability to testthe line for RTD (round trip delays) on the line.
ASKER
Well, I had an interesting Saturday! At first I found myself arguing with one of he "kids"on the oher end of the line when I insisted on following through with my previous troubleshooting session and speaking with a Level 3 supervisor. The "kids" wanted to troubleshoot again! After heated words, I finally hung up and called back and got a woman who seems to know more,( at least she understood the term DHCP) When she configured to new modem (the westell 327w), the router would not recognize the data stream from it. It kept failing over to the (secondary port)Velocity line. Finally, I just stuck the old modem back in and it works. Not any better than before, but at least the office is online. Now, Verizon wants us to buy a T1 line, claiming 25 computers is too much for a single DSL, but isn't a T1 only 1.5mb/s line vs 7.5mb/s or this DSL? Or am I mistaken about the capacities? My next step is to ask if there is a better router/modem combination available.
BTW, I have isolated both the individual lines and checked the traffic. Both lines exhiibit the same "stickiness". And there is no unsual viral traffic.
BTW, I have isolated both the individual lines and checked the traffic. Both lines exhiibit the same "stickiness". And there is no unsual viral traffic.
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Oh, I forgot to mention, we have 3 linksys switches (24port) in a stack. The lines from the different offices coming the the computer room, go through a patch rack and then are distributed to the switches and then through one line to the router. Would it make any difference if, instead, I used the ports of the router to connect one to each switch?
probably not - worth reconfiguring - I think the lady is right about the number of PCs connected - I wonder what's the max number for a domestic router ? (i.e the router has to translate the 5 PCs requests and match up all the responses) did you triy just one PC to the router and see what the lag is like?
glad you got one ofthe grown ups! it reall y is hit or miss with broadband support.
glad you got one ofthe grown ups! it reall y is hit or miss with broadband support.
The T1 vs. DSL is not about speed alone. A normal DSL link is an ADSL, which is asymmetrical. Your down load may be 7.5 Mbps, but your upload may be limited to anywhere from 384Kbps to 768Kbps. You need to check what your upload speeds are.
If by chance something is saturating your upload side (from you to the Internet) then your download side will be severely impacted. A T1 is symmetrical, you have 1.5 Mbps in both direction.
Do you have access to the management interface of the DSL modem? If so can you look at the DSL stats. You want to look at what the attenuation and noise is for both up and down stream. I would also check the up and down stream capacity occupation percentage.
IMHO, depending on what you are actually doing 25 users on an ADSL link is a bit much.
Is there an off hours time where you could go to a test site (http://www.speedtest.net is one I would recommend) and test your upload and download rates.
If by chance something is saturating your upload side (from you to the Internet) then your download side will be severely impacted. A T1 is symmetrical, you have 1.5 Mbps in both direction.
Do you have access to the management interface of the DSL modem? If so can you look at the DSL stats. You want to look at what the attenuation and noise is for both up and down stream. I would also check the up and down stream capacity occupation percentage.
IMHO, depending on what you are actually doing 25 users on an ADSL link is a bit much.
Is there an off hours time where you could go to a test site (http://www.speedtest.net is one I would recommend) and test your upload and download rates.
also domestic ADSL lines usually are 'shared' with the otherusers in the area - the 'contention rate' can be as high as 50:1 which means upto 50 other users in the area can be contending for bandwidth.
ASKER
RE; The performance of one computer-- One computer's response is acceptable but no speed demon. The line tests from speedtest.net and others show 5900kbs down and 750kbs up, which is nominal. This is most likely to be during off-hours. During the day, the speed can vary between nminal and 4900kbs down and 500kbs up.
From what I see here. I'm beginning to think that the internal network load (which has not changed since before this problem started) combined with the contention rate ( which may have changed) is responsible for this issue. How can I check on the contention rate? How could I find out if new scubscribers have been added to the same subnet or to the CO's load?
From what I see here. I'm beginning to think that the internal network load (which has not changed since before this problem started) combined with the contention rate ( which may have changed) is responsible for this issue. How can I check on the contention rate? How could I find out if new scubscribers have been added to the same subnet or to the CO's load?
its probably in the small print of the contract - there is no way for an end user to find out who else is around - you can ask for a lower contention rate (and pay more ) - the hard bit is finding someone at the other end to sort it..
You can't really check the CO's load. chilternPC, is correct, but generally it is not as bad as it sounds. No matter what type of circuit you get to the Internet, at some point in time it is shared.
With cable, is it shared at the neighborhood level.
With dial-up modems it is shared where ever the modem bank is.
With DSL is is shared where ever the DSLAM is located at.
With satellite it is shared at the satellite
With dedicated circuits it is shared at the router the other end is connected to.
These are the "first" point that the bandwidth is shared. Except for cable, the ISP's can upgrade their bandwidth to compensate for additional load. Cable gets a little tough, because they need to change much more to get additional bandwidth to the neighborhood.
Do you have the ability to mirror any of the ports that your Internet traffic flows on? If so I would suggesting getting something (like NTOP) that can show you who is doing what on your Internet connection. Most users don't realize that just a little bit of traffic multiplied by 20-25 users can add up. Things like the little clients that constantly update the weather, playing music in the back ground, watching youtube, etc.
With cable, is it shared at the neighborhood level.
With dial-up modems it is shared where ever the modem bank is.
With DSL is is shared where ever the DSLAM is located at.
With satellite it is shared at the satellite
With dedicated circuits it is shared at the router the other end is connected to.
These are the "first" point that the bandwidth is shared. Except for cable, the ISP's can upgrade their bandwidth to compensate for additional load. Cable gets a little tough, because they need to change much more to get additional bandwidth to the neighborhood.
Do you have the ability to mirror any of the ports that your Internet traffic flows on? If so I would suggesting getting something (like NTOP) that can show you who is doing what on your Internet connection. Most users don't realize that just a little bit of traffic multiplied by 20-25 users can add up. Things like the little clients that constantly update the weather, playing music in the back ground, watching youtube, etc.
Bit Torrent can also cause this effect as it will saturate your upload and cause request and receipt packets to get delayed or droped to time outs.
ASKER
It's very strange, but when we tried a small test of uploading jpg's from the office to our webserver, a test of 3 75k jpg's, the bandwidth usage when from 150k up to 400k up. We did this test with a level3 tech after being routed to the corporate customer service dept. They seemed to care and had the level 3 tech call us. The only thing he could do was change the service type priority rankings in the QoS section of our router. It had only a minimal effect. By that time, the boss had had enough, we switched to Charter Cable DSL. We'll see what happens next week. I also had the idea of using two routers and modems to two separate DSL's and connecting them via the hubs on LAN side f the router. Is this possible and will it work? ( I don't mean Load balancing, which would use two DSL's and one router. We tried that and the logons for IM stalled)
you have 20 PC networked you eed\a proper broadband conection ot a domestic job.
How many people were in the office when you did the test? Getting up to 50% of the available bandwidth might be normal if you were doing the test during the middle of a work day with 20-25 users. I have 12Mbps of bandwidth at my office, during the day I am lucky to get 50% of by bandwidth doing bandwidth tests, however during off hours I can get 100% of my bandwidth.
Did you try http://www.speedtest.net? What where the results?
As for using two DSL connections to one router. You would need to get an ISP that support DSL "bonding" if you wanted both DSL links to appear as a single link. Or you would need to decided to use one DSL link for one type of traffic (say web surfing) and the other DSL link for other types of traffic (say ftp and outbound e-mail).
Did you try http://www.speedtest.net? What where the results?
As for using two DSL connections to one router. You would need to get an ISP that support DSL "bonding" if you wanted both DSL links to appear as a single link. Or you would need to decided to use one DSL link for one type of traffic (say web surfing) and the other DSL link for other types of traffic (say ftp and outbound e-mail).
ASKER
A) As to how many people were in office at the time of the test, I would say 14 people were running computers at the time of the test. Not all were using the web. Some are bookkeeping people, some sales and survery people (using the phone and entering in a local DB), one doing DB work remotely via GoToMyPC. Thus, there were probably four heavy web users, one FTP to company web hosting, and all 14 monitoring AIM.
B) I've used Speedtest.net exclusively. Invariably, the speed reads 5600-7800kps down and 400-750kps up.
C) Interesting idea about assigning specific kinds of traffic to specific DSL lines. That might achieve the benefits of load balancing wihtout having the login problems with AIM that I mentioned above. I assume I can do that under the QoS settings of the router, right?
B) I've used Speedtest.net exclusively. Invariably, the speed reads 5600-7800kps down and 400-750kps up.
C) Interesting idea about assigning specific kinds of traffic to specific DSL lines. That might achieve the benefits of load balancing wihtout having the login problems with AIM that I mentioned above. I assume I can do that under the QoS settings of the router, right?
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As usual with networking, no single thing was the culprit-- except for Verzon's shitty attitude. They never caught on that the boss was ready to switch to Cable Broadband. Three days after the Cable was installed, Verizon called back to ask if here was something they could do. AS if we hadn't told them!!!
So now the office is running on Charter Broadband. It's better but still not 100%. My next move is the check the individual etheret lines for bad cable and connectors. We already found two such lines and repaired them. I'm also going o look at the topology: maybe there are loops/redundancies that are causing packet clashes and extra traffic. Last, I'll look at the idea of separating traffic by type into the two WAN ports.
So now the office is running on Charter Broadband. It's better but still not 100%. My next move is the check the individual etheret lines for bad cable and connectors. We already found two such lines and repaired them. I'm also going o look at the topology: maybe there are loops/redundancies that are causing packet clashes and extra traffic. Last, I'll look at the idea of separating traffic by type into the two WAN ports.
If you had internal network issue (bad cables, loops, ect.) then internal traffic would be slow also. Are you having problem on your internal network?
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yes, there were SOME problems, but nothing seemed to affect performance, which internally was acceptable. I found one or two cables with bad connectors, replaced them No diference. No one ever did an as-built iagram or laelled the wires. So I going to do that in hopes of finding some crazy topology. Maybe a loop somewhere, would that affect performance? Another thought, we have three hubs each with about 15 stations connected to it. They then connect through ONE cable to the router. Would it be better to have THREE wires from the router, each going to a separate hub?
Running 45 computers through a single cable is definitely asking for performance issues. Personally I'd suggest two changes:
1) If your computers talk to each other, rather than just use the Internet: replace all the hubs with switches. A hub shares its speed among all of its ports; a switch can provide full speed to each port. While it won't make a difference when the connection is to the Internet or to a computer that's on a different switch, it would allow computers connected to the same switch to talk to each other without slowing down other computers' connections. The cost isn't high.
2) As you suggested, run separate cables from your router to each hub or switch.
Since everything goes through a single router, you're still going to have potential contention issues for outbound traffic, but these changes will reduce contention between LAN and WAN traffic.
1) If your computers talk to each other, rather than just use the Internet: replace all the hubs with switches. A hub shares its speed among all of its ports; a switch can provide full speed to each port. While it won't make a difference when the connection is to the Internet or to a computer that's on a different switch, it would allow computers connected to the same switch to talk to each other without slowing down other computers' connections. The cost isn't high.
2) As you suggested, run separate cables from your router to each hub or switch.
Since everything goes through a single router, you're still going to have potential contention issues for outbound traffic, but these changes will reduce contention between LAN and WAN traffic.
Do you actually have HUBS, or are you just using the term and you really have switches?
If you really have hubs, then you need to definitely go to switches.
If you really have hubs, then you need to definitely go to switches.
what's a hub?
ASKER
Yes, you're both right. They ARE all switches Netgear JFS-524's. The question remaining then, re: Topology, Is it better to separate traffic by protocol to separate routers and DSL lines or to change sub net masks and spit the LAN into two subnets feeding out through separate routers and DSL's?
Both hubs and switches have multiple ports for computers. The difference is that a hub shares its maximum speed among all the ports, whereas a switch allows each port to run at maximum speed independent of the others. Typical Ethernet speed is 100 Mb/second; if a hub has 10 computers trying to run at full speed, each will only get 10 Mb, while a switch will give each 100 Mb.
Of course, if they're all going out to the Internet, the maximum speed for that connection will be the bottleneck, but if they're talking amongst themselves (file transfers, printing, etc.), the difference in performance could be substantial.
Hubs and switches look essentially the same. You'll have to check the label to make sure which you have. Though come to think of it, I'd be surprised if a device with 16 ports would be a hub; normally you only see those for 4 or 5 ports, because the contention issues become so much more severe as the number of ports grows (and people at the 16-port level aren't typically trying to squeeze pennies quite so tightly).
Of course, if they're all going out to the Internet, the maximum speed for that connection will be the bottleneck, but if they're talking amongst themselves (file transfers, printing, etc.), the difference in performance could be substantial.
Hubs and switches look essentially the same. You'll have to check the label to make sure which you have. Though come to think of it, I'd be surprised if a device with 16 ports would be a hub; normally you only see those for 4 or 5 ports, because the contention issues become so much more severe as the number of ports grows (and people at the 16-port level aren't typically trying to squeeze pennies quite so tightly).
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ChilternPC; A hub is basically a fancy Y-connector. It has no routing capability. A switch has some routing capability, but not as much as a router, and can provide better peformance to all ports.
Based on ChilternPC's profile I hope that question was a joke.
If your Internet connections were symmetrical (upload and download speeds the same) would say splitting the network into "two" and letting 1/2 the users use one and the other 1/2 use the other would be the best.
However, since you are using asymmetrical connection I would suggest you try to do it based on traffic type. This way traffic that normally would generate either more outbound traffic, or equal inbound and outbound would use one connection and traffic that normally generates more inbound than outbound uses the other link.
Examples: http is normally a little traffic out and a lot in, so it would use "connection#1". Now e-mail is normally about equal, so it would use "connection#2". P2P, if you allow this, is also about equal, so it would also use "connection#2".
If your Internet connections were symmetrical (upload and download speeds the same) would say splitting the network into "two" and letting 1/2 the users use one and the other 1/2 use the other would be the best.
However, since you are using asymmetrical connection I would suggest you try to do it based on traffic type. This way traffic that normally would generate either more outbound traffic, or equal inbound and outbound would use one connection and traffic that normally generates more inbound than outbound uses the other link.
Examples: http is normally a little traffic out and a lot in, so it would use "connection#1". Now e-mail is normally about equal, so it would use "connection#2". P2P, if you allow this, is also about equal, so it would also use "connection#2".
oh it was not serious, i didn't they still sold 'hubs' - it was to point out people still use the word 'hub' when they mean swtich. I should have put a smiley afterwards.
<hubs were cheap and cheapful (and not as clever as switches) way back when switches used to be expensive>.
I agree with guiltjr and the network shouldbe split, although I can see users switching connections if the response they have is poor
<hubs were cheap and cheapful (and not as clever as switches) way back when switches used to be expensive>.
I agree with guiltjr and the network shouldbe split, although I can see users switching connections if the response they have is poor
One thing you may want to think about is installing and using a Proxy server.
If the users visit the same sites, then a lot of the static content will be cached locally. If it is cached locally, it will served up faster and reduce network traffic over your Internet connections. If you reduce network traffic over your Internet connections, then the traffic that must still go out over the Internet will have less contention.
Heck I use a proxy server (Squid) in my house and I only have 4 "users" on my home network. Of course I also use the proxy server for URL and content filtering.
If the users visit the same sites, then a lot of the static content will be cached locally. If it is cached locally, it will served up faster and reduce network traffic over your Internet connections. If you reduce network traffic over your Internet connections, then the traffic that must still go out over the Internet will have less contention.
Heck I use a proxy server (Squid) in my house and I only have 4 "users" on my home network. Of course I also use the proxy server for URL and content filtering.
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It's Saturday morning, and with no one in the office, I'm on my way to meet our wiring guy. We're going to be checking for bad connections, bad connectors, and redundancies or loops. In the meantime, I've been thinking about what to do if our efforts today don't improve performance. What's your opinion of the following possible network setup? Break the network into two sub-nets, each sub-net feeding into its own Netgear Router( I have two identical FVS124G 's). Each router connected to a separate DSL line (one phone and one cable). In theory it should work, but there are two issues:
1) Should there be any internal connection between the two routers for workgroup sharing or should each be COMPLETELY separate from the other?
2) How to connect the two subnets? If not an internal connection between routers, does this necessarily mean a VPN connection between them? And what about DHCP? IIf there's an internal connection, do I then have two DHCP servers and, if so, how does each one distinguish which subnet gets which IP#'s? If, on othe other hand, there's a VPN between them does this mean that only one router will serve as DHCP server?
Sorry to drag this so long, and I'm sure you can imagine the boss' frustration.
1) Should there be any internal connection between the two routers for workgroup sharing or should each be COMPLETELY separate from the other?
2) How to connect the two subnets? If not an internal connection between routers, does this necessarily mean a VPN connection between them? And what about DHCP? IIf there's an internal connection, do I then have two DHCP servers and, if so, how does each one distinguish which subnet gets which IP#'s? If, on othe other hand, there's a VPN between them does this mean that only one router will serve as DHCP server?
Sorry to drag this so long, and I'm sure you can imagine the boss' frustration.
--> 1) Should there be any internal connection between the two routers for workgroup sharing or should each be COMPLETELY separate from the other?
Is there a need for them to share resource or to have their computers communicate with each other? If the answer is yes, then they need to connect to each other.
Now for #2 the answer is a bit more difficult. Without knowing the detail of exactly how to configure the FVS124G's the easiest thing would be to connect them to each other using the second WAN port. This would allow you to route traffic between the two LAN segments while keeping them separate from each other. You would have a DHCP on each LAN segment to server up IP address for that segment.
Is there a need for them to share resource or to have their computers communicate with each other? If the answer is yes, then they need to connect to each other.
Now for #2 the answer is a bit more difficult. Without knowing the detail of exactly how to configure the FVS124G's the easiest thing would be to connect them to each other using the second WAN port. This would allow you to route traffic between the two LAN segments while keeping them separate from each other. You would have a DHCP on each LAN segment to server up IP address for that segment.
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Giltjr,
I'm liking your idea more and more. I think my next move will be to use the second router as you suggest. That would put the use of the two DSL's into more of a load sharing mode than a fail-over mode, but that's OK too. As to IP#'s, I guess I would configure the routers like this:
Segment A Segment B
IP's 119.129.229.x 119.129.228.x
Gateway 119.129.229,1 119.129.228.1
subnet Mask 255.225.252.0 255.255.252.0
WAN to other router 119.129.229.0 19.129.228.0
Is that right?
I'm liking your idea more and more. I think my next move will be to use the second router as you suggest. That would put the use of the two DSL's into more of a load sharing mode than a fail-over mode, but that's OK too. As to IP#'s, I guess I would configure the routers like this:
Segment A Segment B
IP's 119.129.229.x 119.129.228.x
Gateway 119.129.229,1 119.129.228.1
subnet Mask 255.225.252.0 255.255.252.0
WAN to other router 119.129.229.0 19.129.228.0
Is that right?
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Understood, but if you have, say, 100 hosts on each subnet (way more than is currently necessary) and you're using 119.129.229.0 for one subnet and 119.129.228.0 for the other ( because 119.129.229.x is the set being used now), and 119.129.230.0 for the router to router connection, then the subnet mask is what? 255.255.254.0?
Even with 255.255.254.0 (/23) you are still talking about 510 hosts per subnet, more that with a 255.255.255.0 (/24)
If you wanted to split that into two subnet, you would need to use a mask of 255.255.255.0. This would allow up to 254 hosts on each subnet.
If you want to reduce the number of hosts allowed to under 254 you need to use a mask like 255.255.255.254 (/25).
A /25 would 126 hosts. To reduce the number of hosts in a subnet you need to increase the number of bits in the subnet mask.
If you wanted to split that into two subnet, you would need to use a mask of 255.255.255.0. This would allow up to 254 hosts on each subnet.
If you want to reduce the number of hosts allowed to under 254 you need to use a mask like 255.255.255.254 (/25).
A /25 would 126 hosts. To reduce the number of hosts in a subnet you need to increase the number of bits in the subnet mask.
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It's been some time since the last development here. Last night I installed a Netgear GSM7248 L2 Managed Switch in the the network. I was surprised to see 2 thngs; 1) it seems to make things go faster because of the Gigbit connections that are now being used internally. Of course,this is subject to a ful load testing during the business day today. 2) Some of workstation connections are still using 10/100 NIC's, including one of heaviest users who does a lot of FTP. That will have to change now that we have Gigabit speed all the way to he internet. Finally, despite being told repeatedly that I could use Layer 3 mangement to form VLANs and route each VLAN to a separate switch port and then to a separate router while maintaining Netbiios (Layer 2) capability internally, I finally found that you can not do that. I finally solved the problem by assigning separate IP's to each router, putting one half of the LAN on one router using DHCP and assigning the other half static IP's with their gateway and DNS server being the second router. Seems to work. We'll see later on today.
Depending on what you mean, you can create a management VLAN for managing the switches.
The links between the switches would be "trunk" (a Cisco term) ports. Meaning that they carry multiple VLAN's traffic and use tagged frames. The switch would have an IP address in the managment VLAN.
Then the ports that the computers talk to would be setup as "access" (another Cisco term) mode ports. Meaning they carry un-tagged frames for a specific VLAN.
This way all user data is on one VLAN and all switch management data is on a second VLAN.
However, it does not seem that this switch supports routing, so you would need a router same palce that is on both VLAN's to route traffic between the VLAN's if the PC's that you manage the switches from are NOT on the same VLAN as the switch management VLAN.
The links between the switches would be "trunk" (a Cisco term) ports. Meaning that they carry multiple VLAN's traffic and use tagged frames. The switch would have an IP address in the managment VLAN.
Then the ports that the computers talk to would be setup as "access" (another Cisco term) mode ports. Meaning they carry un-tagged frames for a specific VLAN.
This way all user data is on one VLAN and all switch management data is on a second VLAN.
However, it does not seem that this switch supports routing, so you would need a router same palce that is on both VLAN's to route traffic between the VLAN's if the PC's that you manage the switches from are NOT on the same VLAN as the switch management VLAN.
I would ask what dsl modems should be used withthe equipment they have at the exchanges.