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Date: Wed, 16 Apr 2014 15:58:42 +0200 From: Yegor Yefremov <yegorslists@...glemail.com> To: Mugunthan V N <mugunthanvnm@...com> Cc: David Miller <davem@...emloft.net>, netdev <netdev@...r.kernel.org> Subject: Re: [net PATCH 1/1] drivers: net: cpsw: Add default vlan for dual emac case also On Wed, Apr 16, 2014 at 7:57 AM, Mugunthan V N <mugunthanvnm@...com> wrote: > On Tuesday 15 April 2014 07:16 PM, Yegor Yefremov wrote: >> On Wed, Apr 9, 2014 at 8:56 PM, David Miller <davem@...emloft.net> wrote: >>> From: Mugunthan V N <mugunthanvnm@...com> >>> Date: Wed, 9 Apr 2014 11:34:40 +0530 >>> >>>> Dual EMAC works with VLAN segregation of the ports, so default vlan needs >>>> to be added in dual EMAC case else default vlan will be tagged for all >>>> egress packets and vlan unaware switches/servers will drop packets >>>> from the EVM. >> Hi Mugunthan, >> >> though this patch fixes drop packets issue, it introduces another >> issue. Just connect both interfaces to one switch and configure >> different subnets. As soon as you get a broadcast you have an endless >> loop and network communication is not possible at all. Before this >> patch you could operate as if you had really two independent NICs. >> >> > > This patch doesn't add any multicast or unicast entry in the ALE table, > so there is no possible way that a broadcast packet is switched within > the two external ports, and this patch removes the encapsulation of the > default vlan id which is used for internal packet switching inside CPSW > switch from host and any packet received from external port will be > tagged with port vlan so internal switching will happen with that port > vlan-id which will be only that physical port and host port. so the > scenario which you mentioned cannot happen theoretically untill you > enable bridge between the dual ethernet interface and connect both to > the same interface. Have you tried the described setup? My system is Buildroot on am335x-evmsk with almost empty /etc/network/interfaces # Configure Loopback auto lo iface lo inet loopback No bridges: # brctl show bridge name bridge id STP enabled interfaces And following address setup made manually: 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 00:18:31:93:f6:49 brd ff:ff:ff:ff:ff:ff inet 192.168.1.234/24 brd 192.168.1.255 scope global eth0 valid_lft forever preferred_lft forever 3: eth1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast state DOWN group default qlen 1000 link/ether 56:90:76:5b:b5:f3 brd ff:ff:ff:ff:ff:ff inet 192.168.4.234/24 brd 192.168.4.255 scope global eth1 valid_lft forever preferred_lft forever 4: wlan0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000 link/ether de:ad:be:ef:00:00 brd ff:ff:ff:ff:ff:ff Routing table: # ip route show 192.168.1.0/24 dev eth0 proto kernel scope link src 192.168.1.234 192.168.4.0/24 dev eth1 proto kernel scope link src 192.168.4.234 Same behavior on 3.14.0-rc4-12740-gcc09039-dirty and 3.15.0-rc1-00002-ge0f8779 As soon as insert the cable into eth1, my switch shows very high activity and the whole LAN in the company is dead till I remove the cable. I have no problems with the version before the fix. I don't really know, what happens inside the driver, but could make the same setup (best of all in a LAN with many Windows PCs, that send lots of broadcast) and let me know if you see the same behavior. Regards, Yegor -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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