Hi, I could be wrong about this, but my understanding of the VSW implementation is that it can only be attached to one physical NIC, VNIC (with Crossbow), or Link Aggregation to run upon. As a result, there shouldn't be an issue of a loop from that end. Now in the case of using IPMP in the guest domains where you have two separate VSWs that are attached to their own physical NIC on the same network, you won't have a loop either as the MAC addresses of those physical links are different. So again, no looping happening.
Now is it possible to connect multiple VSWs together? Yes it is, but it requires an I/O domain to act as a router between them for traffic to be routed. Otherwise, it would be no different than a multi-homed server connected to multiple networks, but providing no routing between them. It is important to understand that the VSW is a dumb layer-2 switch, it's like going to Best Buy and getting a cheap Linksys, Netgear, or DLink switch. The big difference is that you're not limited on the number of ports, no special management features, and it's at the speed of memory and LDCs. So unlike VMware which tries to emulated a switch with ports and settings, VSWs are much simpler. If you want to understand it better, probably a good place to look is the UltraSPARC Hypervisor API document on our community site which talks about some of the low-level functionality happening there. *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-* Octave J. Orgeron Solaris Virtualization Architect and Consultant Web: http://unixconsole.blogspot.com E-Mail: [email protected] *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-* ________________________________ From: "[email protected]" <[email protected]> To: [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected] Sent: Mon, October 4, 2010 6:28:46 AM Subject: [ldoms-discuss] Network related questions concerning vsw spanning tree Hi there thank you for your answers below. Still some questions: My concern regarding virtual switches is the fact that from a network perspective I don’t have control, but I am responsible if network attached servers cause network issues. Primary concern is the fact that in theory it is possible to create layer-2 loops with vswitches. Therefore I would like to know from Oracle/Sun what measures they have taken in order to avoid the creation of Layer-2 loops with virtual switches. I would like to have some documentation of Sun regarding the virtual network implementation within T5240. Please see the splendid vmware documentation reqarding “virtual networking concepts” for example. Here my requirements for virtual switch implementations within servers: -virtual switch isolation is required. It should not be possible to connect 2 or more virtual switches in the same server with each other. What mechanisms are in place on the T5240 to prevent this? -suppose that a virtual switch has 2 fysical uplinks, what mechanisms are in place to prevent the forwarding of a frame coming in on uplink1 to uplink2 (thereby creating a layer-2 loop) It would be apriciated, for our network guys to get a satisfied answer for this. Thanks in adv Anne Adema Martin Qoute:” Hi, For a PoC we're running with LDOMs 1.3 and LDOMs 2.0 I have some questions that hopefully someone can help me with. We're using Solaris 10 9/10 (u9) for control/service domain and guest domains. 1. Does the vswitch participate in Spanning-tree? If yes, can this be disabled? Any differences for LDOMs 1.3 and 2.0 here? No idea, I never observed spanning- tree behaviour of vswitches 2. How can the bandwidth that a VNIC consumes be limited? (Case: we're creating multiple non-global zones in 1 LDOM guest and want to prevent that one non-global zone can take up all bandwidth for a single VNIC). OTOH no way to do this in an I/O domain only without Crossbow. 3. How can we configure "IP Multipathing" for the vswitch with LDOMs 1.3? I know LDOMs 2.0 has this capability... Question: do you want to connect a guest redundantly to the outside world or do you want to connect whole vswitch redundantly to the outside world? 4. Using VLAN tagging on the vswitch, van I assign one VLAN to a VNIC in a guest domain? So that there's a VLAN between the vswitch and the guest, accessible as a VNIC from the guest? Yes. IIRC possible since v1.2, described in the slides on LDOMs under https://sunspace.sfbay.sun.com/x/c9VnDg (sorry only accessible from the Oracle intranet) “ Stefan Quote”: 1. Does the vswitch participate in Spanning-tree? If yes, can this be disabled? Any differences for LDOMs 1.3 and 2.0 here? No idea, I never observed spanning- tree behaviour of vswitches It doesn't have to. It can not be configured to create loops, so we don't need to spanning-tree to protect against them. Externally, it appears as a normal ethernet port, so the real switches at the other end of the cable can do their spanning tree stuff, if they're so inclined. Turning it off completly should'nt be supported on any switch. I assume you mean turning off the spanning tree checking before taking a port online. Cisco switches used to do this, and you could turn this off, as in "go online first, check later, then, if loop detected, take port offline". This would speed up the onlining of ports, but not disable spanning tree checking completely. 2. How can the bandwidth that a VNIC consumes be limited? (Case: we're creating multiple non-global zones in 1 LDOM guest and want to prevent that one non-global zone can take up all bandwidth for a single VNIC). OTOH no way to do this in an I/O domain only without Crossbow. you'll need crossbow for that, as martin already said”
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