CCR-1009-8G-1S WAN Throughput Issue through Arris SB6190 to Metrocast

RouterOS General
1

Mikrotik Experts!

I am experiencing a strange issue and would appreciate some help.

Here is the overall architecture:

Metrocast ISP (90Mbps Down / 9Mbps Up via Cable Modem)
-----Arris SB6190 Cable Modem
---------Linksys 5 Port Gigabit unmanaged Switch
-------------Eth1 - Arris SB6190
-------------Eth2 - CCR1009
--------------------CCR1009 Eth2 - HP Procurve Switch (flat / no VLANS)
--------------------CCR1009 Eth3 - HP Procurve Switch (flat / no VLANS)
--------------------CCR1009 Eth4-8 - PCs (one is my test laptop)
-------------Eth3 - Juniper Netscreen 5GT
-------------Eth4 - Cisco RV082

In this configuration, the Juniper uses a Metrocast provided Static IP. The Cisco RV082 uses a DHCP Public IP from Metrocast. The CCR1009 uses a Metrocast provided Static IP.

Here is the strange result.
From the Cisco Rv082, any PC client can get a speedtest.net result of 90Mbps/9Mpbs (down/up). Same from the Juniper. From the CCR1009, the same PC running the same speedtest.net only gets 36Mbps/9Mbps (down/up).

Here is where it gets really strange… If we make the WAN port on the CCR1009 be a DHCP client, and connect it to a LAN port on the Cisco Rv082, any client on Eth2-8 on the CCR1009 now gets the full Metrocast Line rate of 90Mbps/9Mbps. In other words, the speed actually improves when we move the CCR1009 from the Linksys switch under the Arris SB6190 to the Cisco RV082 which is under the Linksys Switch and Arris SB6190.

We have tried to speak with Metrocast Tier 1 and Tier 2 support and they assure us they are not bandwidth limiting based on MAC address or IP address.

The config in the CCR1009 is about as plain vanilla as it can get. NAT / Masquerade to Eth1. DHCP Server on Bridge with ports Eth2-7. Basic 8 firewall rules.

Any bright ideas of what we can try?

Thanks for the help, I really appreciate it.

2

I don’t think it affects your performance, but please note that on CCR1009 the ports 1-4 are on
a switch, so you should configure it reverse from what is normal on MikroTik routers.
(don’t use ether1 as the ISP port, use ether8. ether1-4 are best used for your directly connected PC’s.)

3

pe1chl,

Thank you for the suggestion.

We tried using Eth8 as the WAN interface and it had no effect. The same exact result was attained in both cases. i.e. Slow speed (36Mbps/9Mbps) when connected directly to the Cable Modem and full speed (90Mbps/9Mbps) when connected to the LAN ports of any other router under the cable modem.

My initial thought is that this is not a Mikrotik configuration issue because the same exact configuration exhibits no issues when passing traffic through another router. It is almost as if the other router NAT’ing and reforming the packets somehow “cleans up” the traffic and therefore it is passed at full speed through the ISP? (Wild speculation here)

My feeling is that perhaps there is something about the Mikrotik’s packets sent out the WAN port that is causing an issue on the Metrocast ISP side. Does anyone have any suggestions about what could be happening in the packets that could be “confusing” the ISP’s routers?

4

Maybe it is some issue at the ethernet level?
Did you by mistake set manual configuration of ethernet at any point?
Don’t do that! Set every port to “auto detect”.
You can check in the ethernet config on the MikroTik what parameters it has set on the port.
When it does not have “full duplex”, the setting of the port at the other device is incorrect.