Date: Thu, 16 Jul 2009 12:50:00 -0400 From: "Jacobs, Brian" <Brian.Jacobs@lodgenet.com> To: "Julian Elischer" <julian@elischer.org> Cc: freebsd-net@freebsd.org Subject: RE: GRE tunnel limitations Message-ID: <126E45722B459248997856ECB72DEB7701285DC2@host.lodgenet.com> In-Reply-To: <4A5F5927.3080904@elischer.org> References: <126E45722B459248997856ECB72DEB7701285DC0@host.lodgenet.com> <4A5F5927.3080904@elischer.org>
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IP unnumbered between the two boxen. I've built some scripts to automatically generate config files, and then other scripts to automagically create the GRE interfaces and inject appropriate routes. GRE numbers are assigned sequentially based on config file lines (and are of no consequence): gre45: flags=3D9051<UP,POINTOPOINT,RUNNING,LINK0,MULTICAST> metric 0 mtu 1476 tunnel inet 10.3.100.39 --> 207.230.84.130 inet 10.3.100.39 --> 10.11.146.129 netmask 0xffffffff=20 gre46: flags=3D9051<UP,POINTOPOINT,RUNNING,LINK0,MULTICAST> metric 0 mtu 1476 tunnel inet 10.3.100.39 --> 12.35.57.131 inet 10.3.100.39 --> 10.10.201.1 netmask 0xffffffff 10.3.100.39 is the primary Ethernet interface address of the local box (terminator). 10.10.201.1 is the inside Ethernet of the remote box. Routing statement for 10.0.0.0/8 live on the remote box, and individual routes live on the concentrator: root@yttrium /root# netstat -nr | grep 10.10.201 10.10.201.0/26 10.10.201.1 UGS 0 2042 gre46 10.10.201.1 10.3.100.39 UH 1 49263 gre46 /bmj -----Original Message----- From: Julian Elischer [mailto:julian@elischer.org]=20 Sent: Thursday, July 16, 2009 12:45 PM To: Jacobs, Brian Cc: freebsd-net@freebsd.org Subject: Re: GRE tunnel limitations Jacobs, Brian wrote: > Does anyone have some realistic data on the number of GRE/ipip tunnels > FreeBSD 7.x can reasonably terminate? Assume no IPsec, just standard > encapsulation. I have an ad-hoc need to terminate about 1,4000 static > GRE tunnels (as Cisco 7206's are backordered until September). J >=20 > =20 >=20 > Thanks in advance! >=20 > =20 >=20 > /bmj >=20 > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" The limitation would be that there is an interface for reach one and=20 the interface 'interface' uses a linked list. it might work but there=20 would probably be scaling issues. I've often thought that what we need is a way to do "bulk encapsulatin=20 interfaces" where there is not an "interface" assigned to each=20 destination. (at least not one that shows up in 'ifconfig'). How will you want to decide which gre interface to use for a given=20 packet? is it just a standard routing decision based on the remote=20 address?
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