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87

Virtual LANs (VLANs) are an abstraction to permit a single physical network to emulate the functionality of multiple parallel physical networks. This is handy because there may be situations where you need the functionality of multiple parallel physical networks but you'd rather not spend the money on buying parallel hardware. I'll be speaking about Ethernet ...


11

Usually overly large ethernet frames can be and are discarded. In the presence of things like jumbo sized frames large ethernet frames are hard to define, so it really depends - but discarding will be probably the most frequent behavior encountered. edit: To elaborate: Standard IEEE 802.3 Ethernet frame size is 1518 bytes, 802.3Q adds 4 bytes to the frame ...


9

I have actually seen this on a cheapo-switch. Someone had connected a switch between a trunk port which had a couple vlans. The frames were forwarded with the vlan tagging intact. The other ports on that switch where able to use the un-tagged vlan. A switch only needs the source/destination mac to decide which ports to forward the frames to, so this ...


7

You need to ensure you have a HDMI v1.3 or 1.4 compliant cable to achieve this, even then you'll never see more than 8.16Gbps due to overhead. I've never seen HDMI being used this way, most sysadmins just buy switches with 10Gig ethernet ports to deal with the...erm, 10Gig ethernet. I like the ideal of the HDMI but it sounds a bit fragile a solution (as is ...


4

You haven't provided any info about the interfaces you're going to use with the fibre link, so I'm guessing that this is 1gbit. If the switches you're going to use have 1gbit copper interfaces aswell then it's no problem to trunk between them, this is the normal way of connecting switches that have several uplinks. I need to warn you however - if those ...


4

What you propose will work, but is not ideal from a redundancy perspective. You propose this: A better topology that would allow for link or core switch failure would be this (note it only uses two fiber ports in the core, but you have a building-to-building link). Obviously spanning tree of some sort must be enabled on all switches to prevent loops: If ...


4

The consumer-class switch will attempt to forward the frame -destination MAC address is all it cares about. If the destination MAC address is not in its CAM table, it will flood the frame out of all its ports, except the one the packet was received from. A switch that uses Cut Through forwarding method will definitely forward the frame, since it begins ...


4

Spillover can approximate failover by setting the Egress Bandwidth on the fast connection to a value much greater than its maximum bandwidth. Assuming wan1 is the fast connection, adding wan1 followed by wan2 to the user configured trunk means that when both connections are up, wan2 will never see any traffic because the bandwidth will never exceed wan1's ...


4

Based on the product brief for the NetXtreme card, it looks like there's support for up to 64 defined VLANs. Configuration is done via the Advanced Control Suite (on page 35). Fundamentally, 802.1q support is implemented before the network traffic gets to the OS. I've been using 802.1q trunks since the Windows 2000 Server days.


4

Distributed Trunking was a means on the ProVision family of HP Switches (35xx/54xx/62xx/66xx/82xx.. not 38xx) to be seen as one switch. It was still two configurations, and there are some features that get disabled on the ProVision switches if enabled. When Distributed Trunking first came out, it was Server to Switch. Its since been improved from switch to ...


3

You need to use the 'ip route 0.0.0.0 0.0.0.0 192.168.1.1' command like you mentioned instead of the existing 'ip default-gateway' command. 'IP route' commands work for all traffic while 'ip default-gateway' is only for traffic originated by that switch. Also unless whatever is attached to Gi0/2 is a switch configured to trunk you don't want Gi0/2 to be a ...


3

Before reading the rest Unfortunately, I don't have enough reputation on the SO-site to ask questions so I've made a lot of rough assumptions in the below answer. Please, please, please elaborate and ask questions before taking action on anything below. The software version The revision isn't the only important piece of information - the "train", or ...


3

When setting up our 5400zl's we had to set one vlan as untagged and tag everything else. It just wouldn't work with all set to tagged.


3

Start simple and iterate. Trunk them together with single GigE. If you've got ~20 workstations and printers in a typical office, you're probably not hitting GigE wire speed at this point anyway. Next step is to do GigE link aggregation (802.3ad). Try 2 GigE connections between each switch, or maybe 4. If your traffic is pretty evenly spread over your ...


3

Best thing to start with is setting up a Trunk Port on one of the four last Ethernet ports, as you will need to Tag all our VLANs out to the next switch. could be best to buy the same vendor (DLINK) as i've had to do a few firmware upgrades on DLINK's myself to get them to properly tag packets for and trunk It also sounds like you want to setup an ...


3

The following lines on the spec-sheet are the interesting ones: IEEE 802.1Q Static VLAN (256 groups, Static) -- Supports VLANs IEEE802.3ad Link Aggregation (manual or LACP) -- Supports trunking Since you only have a single LAN port on your server, trunking probably won't do anything for you. You can feed multiple VLANs to a single port.


2

VLANs are "Virtual Local Area Networks". The following is my understanding - my background is primarily Systems Engineering & Administration with a side of OO programming & much scripting. VLANs are intended to create an isolated network across multiple hardware devices. A traditional LAN in older times might only exist where you have a single ...


2

The important parts of your log are these two WARNING messages: [2012-08-01 09:08:11] WARNING[3921] chan_sip.c: Retransmission timeout reached on transmission 3e57de11239b49f10930969c7e23d1ca@50.58.42.81:5060 for seqno 102 (Critical Request) -- See https://wiki.asterisk.org/wiki/display/AST/SIP+Retransmissions Packet timed out after 9983ms with no response ...


2

Get a networking specialist to do it. Seriously. In modern networks, trunking generally refers to the idea of passing multiple VLANs from one switch to another, not teaming switch ports for more bandwidth, which probably won't help anyway. Get a faster switch, get faster NICs on the server sending out this HD video, get QoS in place, get... well, a ...


2

Intra-VLAN Routing In your first question, your correct in your first assumption that users in VLAN 0 won’t be able to contact users in VLAN 2, to include the l3-interface you have set up on SW3, but only because you haven’t set up a default-gateway on PC2 or SW3. What is the next thing a host does if it sends out a broadcast on its VLAN and receives ...


2

There is a redundant path in the network as the loop between SW3 and SW6 is closed.There is no broadcast storm in the network? What is the reason for this? Spanning Tree Protocol


2

LACP is the Link Aggregation Control Protocol. It is all about setting up link aggregation automatically and dynamically whenever more than one link is available and the other side speaks LACP as well. It typically is used with redundant server-switch interconnection since a static setup with link aggregation would break server connectivity as long as the ...


2

The issue was this was found to be that by default Spanning-tree was enabled on the 2848 Layer2. If I plugged another branded switch into the Layer 3 6248 and then the other switch into the 2848 it would work. Going from the Dell to Dell would not work at all. Turning off STP on the 2848 solved this issue. I have also found that using "spanning-tree ...


2

As user97408 points out, you should change the mode of the backup interface to Passive. If you only have one Active interface, the load balancing algorithm selection doesn't really matter. (Screenshot Edit WAN_TRUNK) I have also enabled Connectivity Check in the settings of each wan Ethernet interface, as in my setup the ZyWall is unlikely to see link loss ...


2

OK I just had this happen between an older PiaF (1.4) box and a new one running asterisk 1.6. Turns out newer asterisk has added some security features that need to be turned off to be intercompatible. It actually turned out the messages were in the asterisk log file, though I wasted 2 hours before seeing them: [2011-01-18 02:39:01] ERROR[15257] ...


2

SFP is a smaller form factor of GBIC. Both GBIC and SFP were designed to be swappable/pluggable interfaces. SFP (small-form pluggable) is just more efficient in terms of size, with SFP+ being a compatible interface with increased speed.


2

Put the two devices on ports associated with the same VLAN (untagged ports) and either disable tagging on the devices, or just let them communicate with each other without adding any logic to the ports. Can you tell us what the devices are, as this seems like an odd request.


2

You stated that ports 3 and 42 were configured on the Catalyst switch, but then provided configurations for ports 46 and 48. The configuration you posted for port 46 should be applied to port 3 that connects to the EX2200. Your router's connection is unchanged, so hopefully we can assume that configuration is fine. Now, on the EX2200, the following lines of ...


2

A lengthy solution ... So I've been toying around with different concepts and I think I've made a workable solution. Basically, there is a main bridge trunk (bt) that eth0 belongs to. Then for each firewall VM has its own bridge. bridge name bridge id STP enabled interfaces bt 8000.002618895a72 no eth0 ...



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