Packet Loss on at&t U-Verse Circuit

WildMonkey365

Commendable
Aug 30, 2016
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I just installed an Edgemarc 4700 on one of these circuits and when I got the device online I started pinging to both the public address of the Edgemarc & the ISP Gateway public address. The Edgemarc is in Alabama and I ran pings from my office in Philadelphia. The Gateway did not drop any packets but the Edgemarc did. Immediately I began to troubleshoot the Edgemarc since it was dropping a ton of packets. I was able to ssh into the Edgemarc and ran pings to 8.8.8.8, CNN.com and the Public Gateway address (modem). All these pings dropped a ton of packets. The at&t modem has a LAN gateway of 192.168.50.1 which I verified the MAC address in the Edgemarc arp table that it actually is the modem. When I ping it from the Edgemarc I don't drop any packets which makes me think that it is an ISP problem since there is no packet loss on any LAN IP's. I also had the installer test the cable between the Edgemarc and the modem and it passed. I ran also ran a Capture on the WAN port while I pinged external addresses from the Edgemarc and ping from Philadelphia. On the pcap I saw a few "no replies" but none to the public address of the Edgemarc. Is this conclusive evidence that the ISP is to blame?
 
Solution
The ISP will never take blame if they can avoid it. They will say it is another ISP in the path when you ping stuff like 8.8.8.8 or cnn.

The only test that does much good is to ping the lan IP (from the lan of course) of the router. Then run a tracert and ping normally the second hop. This is the ISP first router in the path. You hope to prove that you local equipment including your router is fine but there is a problem as soon as it leaves your location. They can try to blame a modem or wiring in your building but other than that it proves it is their issue.

Now if the lose is actually farther into the network ...ie it is not in the cable between you and the ISP it gets very hard to get these fixed. It can really be that...
The ISP will never take blame if they can avoid it. They will say it is another ISP in the path when you ping stuff like 8.8.8.8 or cnn.

The only test that does much good is to ping the lan IP (from the lan of course) of the router. Then run a tracert and ping normally the second hop. This is the ISP first router in the path. You hope to prove that you local equipment including your router is fine but there is a problem as soon as it leaves your location. They can try to blame a modem or wiring in your building but other than that it proves it is their issue.

Now if the lose is actually farther into the network ...ie it is not in the cable between you and the ISP it gets very hard to get these fixed. It can really be that that there is a problem between ISP such as not enough capacity.
 
Solution
Very good point. Do you know of any reason why the the Public Address of the ISP Gateway is not dropping pings but the router I installed is? When I ping both public addresses from my fiber circuits the only IP that will drop pings is the router I installed?
 
I am still not 100% sure what you have tested. But It sounds like you have 2 routers cascaded. If both the att modem/router and the edmarc device both have public ip it is a unusual install.

I would attempt to use the ATT device as only a modem which should put your edmarc device on the internet more or less directly.

 


 
Got you. Nothing is double natted. The modem and the router I installed both have a Public Address but the public address of the modem is the WAN gateway IP of the router I installed. The modem also has a router that does NAT if the customer wants to use the modem as their firewall. I'm not sure what business class cable circuits are like where your from but it is just like a Comcast Xfinity modem/circuit. On the modem the LAN IP is accessible from my router and makes an entry into my routers Arp table which is the same MAC address as the public gateway IP. If I plug a laptop into the modem it will give me a 192.168.50.0/24 address. The true way to prove beyond a shadow of a doubt where the packet loss lies is for me to put a Hub in between my router and he modem and run pings to my routers public address and run pings from my router, take a Capture and see if the interface on my router drops pings. But since the customer is in Alabama it makes things harder.