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knet1
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Wan aggregation

Sun Nov 10, 2019 12:07 am

Is there a way to aggregate 2 wan adsl with a mikrotik router and routeros chr; combine the 2 wan into one and use chr ip address for incoming and outgoing traffic?
 
sindy
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Re: Wan aggregation

Sun Nov 10, 2019 1:40 pm

Is there a way to aggregate 2 wan adsl with a mikrotik router and routeros chr; combine the 2 wan into one and use chr ip address for incoming and outgoing traffic?
If you have in mind that the CHR would run on a public address in some data center, then yes. You create two VPN tunnels between the CHR and the RB at home, one via each ADSL uplink, and use the two tunnels as routes to internet. However, like with any other link aggregation, there is no trouble-free way to use the bandwidth of both links for a single connection (in terms of TCP session). So you have to choose a strategy of distributing the load among the links in both directions which will match your application scenario best.
Instead of writing novels, post /export hide-sensitive. Use find&replace in your favourite text editor to systematically replace all occurrences of each public IP address potentially identifying you by a distinctive pattern such as my.public.ip.1.
 
knet1
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Re: Wan aggregation

Sun Nov 10, 2019 9:01 pm

If i use always for outgoing and incoming traffic the public ip of the chr you believe that i will still have issues with tcp connections?
 
sindy
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Re: Wan aggregation

Sun Nov 10, 2019 9:36 pm

If i use always for outgoing and incoming traffic the public ip of the chr you believe that i will still have issues with tcp connections?
The kind of issues I had in mind comes from shuffled order of packets at receiving side as some TCP stacks don't deal well with that. That's why every networking technology I've heard of tries to keep all packets of the same TCP session on the same physical path.

As the packets tend to come in bursts, even if both ADSL modems are actually connected to the same DSLAM, the packets may overtake each other. Imagine a larger packet coming first, being sent via ADSL 1, and then a much smaller packet coming right next, being sent via ADSL 2. But the transport time of the packet through the ADSL over, say, 5 Mbit/s uplink is much longer than the transport time from the router to the modem over a 100 Mbit/s LAN link, so the shorter packet crawls to the DSLAM before the longer one, and here we go.

So the source and destination addresses of all the packets will be allright, but although no packets will get actually lost, useless retransmissions may take place depending on the behaviour of the sending and receiving TCP stacks (e.g. if the receiving stack eagerly sends an ACK for the above mentioned small packet, indicating a gap before it by means of the SACK mechanism).
Instead of writing novels, post /export hide-sensitive. Use find&replace in your favourite text editor to systematically replace all occurrences of each public IP address potentially identifying you by a distinctive pattern such as my.public.ip.1.

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