4 months old thread, but (since I'm starting to test some QinQ stuff just now), I found both this thread and its «solution»:
PR1413700 «Untagged traffic is single-tagged in Q-in-Q scenario on EX4300 platforms» «On EX4300 platforms except for EX4300-48MP with Q-in-Q configured, untagged traffic over S-VLAN is forwarded with a single tag, whose processing behavior is not in line with other products (e.g., the MX platforms) and other providers (e.g., Cisco). If Q-in-Q is configured between these devices with different processing behavior of untagged traffic, this might cause the untagged traffic loss.» So if I understand well, they suddenly chose compatibility with Cisco & MX instead of compat with old EX (whereas an option would have been fine). The problem is: I'm not sure at all that it's really the case on Cisco gears... > Le 24 mars 2019 à 16:36, Alexandre Snarskii <s...@snar.spb.ru> a écrit : > > On Fri, Mar 22, 2019 at 04:21:47PM -0400, Andrey Kostin wrote: >> Hi Alexandre, >> >> Did it pass frames without C-tag in Junos versions < 18? > > Yes. > > tcpdump from upstream side when switch running 17.4R1-S6.1: > > tcpdump: listening on ix1, link-type EN10MB (Ethernet), capture size 262144 > bytes > 17:59:15.742379 0c:c4:7a:93:a6:8e > ff:ff:ff:ff:ff:ff, ethertype 802.1Q > (0x8100), length 64: vlan 171, p 0, ethertype ARP, Ethernet (len 6), IPv4 > (len 4), Request who-has 10.11.1.2 tell 10.11.1.1, length 46 > 17:59:16.773827 0c:c4:7a:93:a6:8e > ff:ff:ff:ff:ff:ff, ethertype 802.1Q > (0x8100), length 64: vlan 171, p 0, ethertype ARP, Ethernet (len 6), IPv4 > (len 4), Request who-has 10.11.1.2 tell 10.11.1.1, length 46 > > exactly the same setup, switch upgraded to 18.3R1-S2.1: > > 18:19:28.535143 0c:c4:7a:93:a6:8e > ff:ff:ff:ff:ff:ff, ethertype 802.1Q > (0x8100), length 68: vlan 171, p 0, ethertype 802.1Q, vlan 1, p 0, ethertype > ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 10.11.1.2 tell > 10.11.1.1, length 46 > 18:19:29.598700 0c:c4:7a:93:a6:8e > ff:ff:ff:ff:ff:ff, ethertype 802.1Q > (0x8100), length 68: vlan 171, p 0, ethertype 802.1Q, vlan 1, p 0, ethertype > ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 10.11.1.2 tell > 10.11.1.1, length 46 > > as you see, packets that were transferred with only S-vlan tag > now encapsulated with both S-vlan and 'native' vlan.. > > >> >> Kind regards, >> Andrey >> >> Alexandre Snarskii писал 2019-03-22 13:03: >>> Hi! >>> >>> Looks like JunOS 18.something introduced an incompatibility of native >>> vlan handling in QinQ scenario between ELS (qfx, ex2300) and non-ELS >>> switches: when ELS switch forwards untagged frame to QinQ, it now adds >>> two vlan tags (one specified as native for interface and S-vlan) >>> instead >>> of just S-vlan as it is done by both non-ELS and 'older versions'. >>> >>> As a result, if the other end of tunnel is non-ELS (or third-party) >>> switch, it strips only S-vlan and originally untagged frame is passed >>> with vlan tag :( >>> >>> Are there any way to disable this additional tag insertion ? >>> >>> PS: when frames sent in reverse direction, non-ELS switch adds only >>> S-vlan and this frame correctly decapsulated and sent untagged. >>> >>> ELS-side configuration (ex2300, 18.3R1-S1.4. also tested with >>> qfx5100/5110): >>> >>> [edit interfaces ge-0/0/0] >>> flexible-vlan-tagging; >>> native-vlan-id 1; >>> mtu 9216; >>> encapsulation extended-vlan-bridge; >>> unit 0 { >>> vlan-id-list 1-4094; >>> input-vlan-map push; >>> output-vlan-map pop; >>> } >>> >>> (when native-vlan-id is not configured, untagged frames are not >>> accepted at all). >>> _______________________________________________ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp