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colin
newbie
Topic Author
Posts: 27
Joined: Mon May 11, 2015 11:11 am

vrrp with mtu

Fri Dec 21, 2018 4:27 am

Does anyone know how to change mtu of vrrp interface?

The default value is 1500, and i change it to 1512 or 1480, but the actual mtu is still 1500

And it seems that it no effect to pppoe interface which created base on vrrp, for example:
eth1 mtu:1500
vrrp1 mtu:1460
pppoe1 mtu:1480
pppoe1 can connect successfully.
 
sathackr
just joined
Posts: 8
Joined: Thu Dec 25, 2014 5:13 am

Re: vrrp with mtu

Thu Jan 10, 2019 5:17 am

I'm seeing the same thing.

vrrp set on vlan interface.

physical inteface mtu is 10222
vlan interface mtu is 9170
vrrp interface mtu set to 9170 but actual mtu is 1500

this is on CCR-1072, RouterOS v6.42.11


config:
[admin@MikroTik1] > export compact
# jan/09/2019 19:30:00 by RouterOS 6.42.11
# software id = SYGW-LSV5
#
# model = CCR1072-1G-8S+
# serial number = XXXXXXXXXXXX
/interface ethernet
set [ find default-name=ether1 ] l2mtu=9116 mtu=9116
set [ find default-name=sfp-sfpplus1 ] l2mtu=10222 mtu=10222
set [ find default-name=sfp-sfpplus2 ] disabled=yes l2mtu=10222 mtu=10222
set [ find default-name=sfp-sfpplus3 ] disabled=yes l2mtu=10222 mtu=10222
set [ find default-name=sfp-sfpplus4 ] disabled=yes l2mtu=10222 mtu=10222
set [ find default-name=sfp-sfpplus5 ] disabled=yes l2mtu=10222 mtu=10222
set [ find default-name=sfp-sfpplus6 ] disabled=yes l2mtu=10222 mtu=10222
set [ find default-name=sfp-sfpplus7 ] disabled=yes l2mtu=10222 mtu=10222
set [ find default-name=sfp-sfpplus8 ] disabled=yes l2mtu=10222 mtu=10222
/interface vlan
add interface=sfp-sfpplus1 mtu=9170 name=vlan100-L3_MX960 vlan-id=100
/interface vrrp
add interface=vlan100-L3_MX960 interval=200ms mtu=9170 name=vrrp1 \
    priority=101 vrid=101
/interface wireless security-profiles
set [ find default=yes ] supplicant-identity=MikroTik
/ip address
add address=10.10.7.5 interface=vrrp1 network=10.10.7.5
add address=10.10.7.2/29 interface=vlan100-L3_MX960 network=10.10.7.0
/ip route
add distance=1 gateway=10.10.7.1
/system clock
set time-zone-name=America/Chicago
/system identity
set name=MikroTik1
[admin@MikroTik1] >
 
sathackr
just joined
Posts: 8
Joined: Thu Dec 25, 2014 5:13 am

Re: vrrp with mtu

Thu Jan 10, 2019 5:20 am

Appears to be just cosmetic.

8000 byte ping packet works when sourced from vrrp IP address with do-not-fragment set.
[admin@MikroTik1] > ping 10.10.7.1 size=8000 do-not-fragment src-address=10.10.7.5
  SEQ HOST                                     SIZE TTL TIME  STATUS
    0 10.10.7.1                                8000  64 1ms
    1 10.10.7.1                                8000  64 1ms
    2 10.10.7.1                                8000  64 1ms
    3 10.10.7.1                                8000  64 1ms
    4 10.10.7.1                                8000  64 1ms
    5 10.10.7.1                                8000  64 1ms
    6 10.10.7.1                                8000  64 1ms
    7 10.10.7.1                                8000  64 1ms
    8 10.10.7.1                                8000  64 1ms
    sent=9 received=9 packet-loss=0% min-rtt=1ms avg-rtt=1ms max-rtt=1ms

[admin@MikroTik1] >

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