It's as expected; you have to use vlan-tagging to add the 4 bytes to the MTU. It's a documentation error.
Thank you, -- Doug Hanks - JNCIE-ENT #213, JNCIE-SP #875 Sr. Systems Engineer Juniper Networks On 2/9/12 4:29 PM, "Dawid Gajownik" <gajow...@gmail.com> wrote: >Hi! > >I've been troubleshooting today MTU issues on my new MX80 router >(actually MX5) with Junos 11.4R1.14. I have noticed that MTU of >interfaces differs if I set trunks with old-style or new-style >configuration. > >Documentation >http://www.juniper.net/techpubs/en_US/junos11.4/topics/example/layer-2-bri >dge-domain-environment-example-interfaces-and-vlans-mx-solutions.html >does not mention it, but with a interface-mode you have to manually >set MTU 4 bytes larger or add "vlan-tagging" option. Is this a bug in >Junos or documentation is incomplete? On EX4200 with interface-mode I >did not need to add/change anything. > >Please take a closer look at ae1 interface: > >root@KR-020-r1# show ae0 >description "### KR-011-s1 ###"; >vlan-tagging; >encapsulation extended-vlan-bridge; >aggregated-ether-options { > lacp { > active; > periodic fast; > } >} >inactive: unit 0 { > family bridge { > interface-mode trunk; > vlan-id-list [ 708 206 ]; > } >} >unit 206 { > vlan-id 206; >} >unit 708 { > vlan-id 708; >} > >[edit interfaces] >root@KR-020-r1# show ae1 >description "### KR-020-s1 ###"; >aggregated-ether-options { > lacp { > active; > periodic fast; > } >} >unit 0 { > family bridge { > interface-mode trunk; > vlan-id-list [ 708 206 ]; > } >} > >[edit interfaces] >root@KR-020-r1# show ae2 >description "### KR-020-s2 ###"; >mtu 1518; >aggregated-ether-options { > lacp { > active; > periodic fast; > } >} >unit 0 { > family bridge { > interface-mode trunk; > vlan-id-list [ 708 206 ]; > } >} > >[edit interfaces] >root@KR-020-r1# show ae3 >description "### KR-020-s3 ###"; >vlan-tagging; >aggregated-ether-options { > lacp { > active; > periodic fast; > } >} >unit 0 { > family bridge { > interface-mode trunk; > vlan-id-list [ 708 206 ]; > } >} > >[edit interfaces] >root@KR-020-r1# run show interfaces ae0 | grep MTU > Link-level type: Extended-VLAN-VPLS, MTU: 1518, Speed: 2Gbps, BPDU >Error: None, MAC-REWRITE Error: None, Loopback: Disabled, Source >filtering: Disabled, Flow control: Disabled, > Protocol bridge, MTU: 1518 > Protocol bridge, MTU: 1518 > Protocol multiservice, MTU: Unlimited > >[edit interfaces] >root@KR-020-r1# run show interfaces ae1 | grep MTU > Link-level type: Ethernet, MTU: 1514, Speed: Unspecified, BPDU >Error: None, MAC-REWRITE Error: None, Loopback: Disabled, Source >filtering: Disabled, Flow control: Disabled, > Protocol bridge, MTU: 1514 > >[edit interfaces] >root@KR-020-r1# run show interfaces ae2 | grep MTU > Link-level type: Ethernet, MTU: 1518, Speed: 2Gbps, BPDU Error: >None, MAC-REWRITE Error: None, Loopback: Disabled, Source filtering: >Disabled, Flow control: Disabled, > Protocol bridge, MTU: 1518 > >[edit interfaces] >root@KR-020-r1# run show interfaces ae3 | grep MTU > Link-level type: Ethernet, MTU: 1518, Speed: Unspecified, BPDU >Error: None, MAC-REWRITE Error: None, Loopback: Disabled, Source >filtering: Disabled, Flow control: Disabled, > Protocol bridge, MTU: 1518 > Protocol multiservice, MTU: Unlimited > >[edit interfaces] >root@KR-020-r1# > >Regards, > Dawid >_______________________________________________ >juniper-nsp mailing list juniper-nsp@puck.nether.net >https://puck.nether.net/mailman/listinfo/juniper-nsp _______________________________________________ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp