No, not the L2 MTU. The L3 (IP) MTUs must match on the router interfaces
speaking OSPF.
I have zero experience with SIAE gear, but being a licensed radio, I
imagine it has an integrated ethernet switch. I've seen a fair number of
switches go stupid. If you can run 1500 byte pings across the link with
no loss, then I'd assume both L2 and L3 should work as expected.
However, that doesn't mean something isn't screwing with multicast,
which OSPF obviously needs.
On 7/5/2017 10:15 PM, Jason McKemie wrote:
I checked, all MTUs on these links are the same. The L2 MTU, however,
is not. Does this have any effect?
On Wed, Jul 5, 2017 at 10:12 PM, Jason McKemie
<[email protected]
<mailto:[email protected]>> wrote:
No errors or packet loss. Strangely, it seems to be preferring
the Rocket M5 backhaul over the SIAE 11GHz link. The MTU on both
ends of the link has remained at default on these. I'll double
check, but unless it changed itself it should be the same.
On Wed, Jul 5, 2017 at 8:13 PM, George Skorup
<[email protected] <mailto:[email protected]>> wrote:
Errors or packet loss? Something rate limiting multicast? Has
someone recently changed MTUs? I don't know if RouterOS will
even log OSPF MTU mismatches. Never tried it. If the IP/L3
MTUs don't match, then OSPF is not gonna have a good time.
OSPF relies on IP since there is no native fragmentation in
the protocol.
As far as NTP and/or accurate time, I haven't experienced any
issues with that in regards to OSPF. I discovered a router
where the NTP process appeared to have crashed and the clock
was off by like 10 minutes. OSPF was humming along with two
neighbors for months and a third for hours because the
adjacent router was rebooted.
On 7/5/2017 7:20 PM, Darin Steffl wrote:
I also recommend only using bug fix release for mikrotik.
Also make sure you have clocks synced to an ntp source on
every mikrotik router and that it's accurate.
On Wed, Jul 5, 2017 at 7:09 PM Jason McKemie
<[email protected]
<mailto:[email protected]>> wrote:
Thanks. I'll try 6.38.7 tonight.
There haven't been many changes to the network, and every
is pingable. I did add one static route for a Baicells
eNB a week or two ago, but the problem cropped up more
recently. I'll have to look into that a bit more.
On Wed, Jul 5, 2017 at 6:59 PM, Chris Wright
<[email protected] <mailto:[email protected]>> wrote:
I recommend sticking to the Bugfix releases
(currently 6.38.7).
Did anything happen recently that could possibly have
provoked the disappearance like a VLAN or other L2/L3
change? Are the neighbors pingable on their backbone IPs?
Chris Wright
Network Administrator
*From:*Af [mailto:[email protected]
<mailto:[email protected]>] *On Behalf Of *Jason
McKemie
*Sent:* Wednesday, July 05, 2017 4:53 PM
*To:* [email protected] <mailto:[email protected]>
*Subject:* [AFMUG] Mikrotik OSPF
Has anyone seen issues with Mikrotik OSPF neighbors
just disappearing for no apparent reason? All of my
links are ok, but I OSPF just isn't picking anything
up on one of them. I might try upgrading both of the
Mikrotiks involved, this feels like a bug. I have
6.38.5 on one end and 6.38 on the other, both CCR's.
--
Darin Steffl
Minnesota WiFi
www.mnwifi.com <http://www.mnwifi.com/>
507-634-WiFi
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