Date: Wed, 20 Feb 2002 00:16:56 -0800 (PST) From: Alexander Grebennikov <algr@rocc.ru> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/35136: VLAN & bridging & MTU Message-ID: <200202200816.g1K8GuH51911@freefall.freebsd.org>
next in thread | raw e-mail | index | archive | help
>Number: 35136 >Category: kern >Synopsis: VLAN & bridging & MTU >Confidential: no >Severity: serious >Priority: medium >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Wed Feb 20 00:20:01 PST 2002 >Closed-Date: >Last-Modified: >Originator: Alexander Grebennikov >Release: tried many up to 4.4-RELEASE >Organization: RCC >Environment: FreeBSD x2.rocc.ru 4.4-RELEASE FreeBSD 4.4-RELEASE #0: Thu Dec 20 11:11:47 MSK 2001 >Description: I'm trying to bridge traffic between 2 VLANs using FreeBSD in BRIDGE mode. Channel between 2 VLANS going through G.703. There are 2 G.703<-->Ethernet converters at both sides. Converters are modems. These modems cannot pass VLAN packets because VLAN packets are 4 bytes large then usual. What i did: setting up 1-st interface on FreeBSD with MTU=1500 , second interface ( to converter) with MTU=1400. Started BRIDGE mode. Packets not fragmented passing FreeBSD. :( And still getting out to converter with MTU=1500 via ethernet interface with MTU=1400 !! I think it's a bug ?? >How-To-Repeat: Need 3 computers: 2 of them - usual PCs with 1 Ethernet card each. 3-rd = FreeBSD in Bridge mode with 2 ethernet cards. 1 card must be setted MTU=1500. Second card - MTU=1400 E.g. PC1 <--(MTU_1500)-->FreeBSD_BRIDGE<--(MTU_1400)--> PC2 Ping PC2 from PC1 with packet size=4000 byes (for example) Start to sniff packets from PC1 on PC2. They should have maximum size=1400 bytes ! But they will have size =1500 ! That is bug. >Fix: I don't know.... >Release-Note: >Audit-Trail: >Unformatted: To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-bugs" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200202200816.g1K8GuH51911>