Hello again... I didn't specify comcast but in the context of our discussion it doesn't matter much :)
Tom... Lets just do a test from your network to mine. A learning experience if nothing else - can't go wrong there. I've never heard of CIPE but I assure you that MT has no problem whatsoever passing traffic from anyone over a tunnel between us, I think you are hung up on something that is a non-issue and what Butch mentioned was not about over one's own network - he understood that it was from some end user provider to another with multiple possible ISPs in the middle... its a mute point who's in the middle really with whats being proposed and how it works. I have a router ready to go, you? Latency between us is good, less than 30ms. I 60MB on any given day/time still available not doing anything, usually a little more. Scott Carullo Brevard Wireless 321-205-1100 x102 -------- Original Message -------- > From: "Tom DeReggi" <[email protected]> > Sent: Sunday, April 26, 2009 6:49 PM > To: "WISPA General List" <[email protected]> > Subject: Re: [WISPA] Interesting BGP Redundancy Opton for FREE > > Butch, > > You completely missed my point, ot the background to the thread.. > Of course "you" can build a tunnel of just about any MTU size on "your" > network. > The issue at hand is what max MTU size OTHER upstream ISPs allow on their > network. > > Scott was talkng about doing a tunnel accross an end user Comcast circuit. > With the open Internet, the two end point end users don't really have > control of what ISPs in between gets traversed from End Point A to B. The > ISPs in the middle could chance at any time. This is not a new problem.... > > For example.... A number of years back Universities built a "private" > experimental transport network to support high MTU above 9600, so that their > GB and 10GB networks could pass full capacity. As you know, max transfer > rate is directly proportional to latency times packet size. Most common ISPs > only passed 1500MTU, therefore the Universities had to make their own net. > This has been a challenge for years for even passing VLAN tags or MPLS data, > where layer2 fiber carriers would only pass a 1512 packet. When you are the > end user, the answer is to shrink your MTU, so after the tunnel overhead it > fits into the ISP's max 1512 MTU. But when one is an tranport ISP that > transports many customer's data, it is not appropriate for the ISP to shrink > his MTU below 1500, as all the other end users would not know that the MTU > was shrunk, and would not have their routers set to a smaller MTU to fit. > > Sure you can allow fragmentation, and TCP will automatically split the > packets to fit, but it has been common ISP management practice to disallow > fragmentation for various reasons that I don't want to get into in this > thread. And yes, there is MTU autolearning, but again, not supported by > everyone or all protocols. > > So sure, the ISP can make a tunnel setting a lower MTU, so after tunel > overhead, it will fit in the uipstream's 1512 MTU. But then full size > packets (because packets comming from end user customers will be 1512 size) > inside the tunnel will get fragmented to fit into the tunnel. For long haul > backhauls, there can be side effects of just simply allowing fragmentation > on the routers without any further consideration. > > Again, we have a good solution for this... It is called CIPE. Its a > tunneling protocol that splits the packets appropriately for optimal > efficiency. I understand how CIPE works because it is what we use. I can't > say I understand the methods that Mikrotik may use. So, what I asked is how > Mikrotik can deal with that problem, because Mikrotik does not support CIPE. > > > Tom DeReggi > RapidDSL & Wireless, Inc > IntAirNet- Fixed Wireless Broadband > > > ----- Original Message ----- > From: "Butch Evans" <[email protected]> > To: "WISPA General List" <[email protected]> > Sent: Friday, April 24, 2009 11:03 PM > Subject: Re: [WISPA] Interesting BGP Redundancy Opton for FREE > > > > On Fri, 2009-04-24 at 19:37 -0400, Tom DeReggi wrote: > >> Over a Layer2 PTP its usually not an issue, but it is over a standard > >> transit connection. > >> (customer and Internet needs to see 1500 bytes, but an ISP's tunnel > >> causes > >> packet size to exceed 1500 MTU. > > > > I have built tunnels that carry 12000 byte packets. Not sure where this > > idea comes from. They can be built that will carry as much as 65k > > bytes. > > > >> We use Cipe tunnels to solve that. To split the full size packets before > >> it > >> enters the tunnel, so tunnel stays at 1500MTU or less, required by the > >> transit provider.. > >> > >> How do you do it with Mikrotik ? > > > > Of the tunnels I've done with MT, you just use PPtP and set the MRRU > > (just like your tunnels). I've done this with standard Linux, too. It > > is actually quite an elegant solution. > > > > -- > > ******************************************************************** > > * Butch Evans * Professional Network Consultation* > > * http://www.butchevans.com/ * Network Engineering * > > * http://www.wispa.org/ * WISPA Board Member * > > * http://blog.butchevans.com/ * Wired or Wireless Networks * > > ******************************************************************** > > > > > > > > > > ---------------------------------------------------------------------------- ---- > > WISPA Wants You! 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