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0answers
51 views

Do you need STP on ProCurve trunks?

We have 3 switches - a Core Switch, and 2 downstream switches. Each downstream switch has a 3 cable Trunk direct to the core switch. However - when we disconnected one cable in that trunk group ...
0
votes
1answer
243 views

cascading load on connected Alcatel-Lucent OmniSwitch units via VLANs

We are having an intermittent issue with a campus of Alcatel-Lucent Omniswitch switches, ranging from model 6000 to 6850. We are having a problem tracking down the root cause of our issue. The seems ...
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2answers
100 views

Avoiding switch loop

Will I have loop problems with this topology because S2 and S3 are both connected to S1 and s4 ?
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1answer
350 views

DHCP over PXE fails, but in the OS it works - with configured (R)STP

I'm trying to PXE-boot desktop-machines to install a new OS over the network, but it isn't picking up an IP address via DHCP during boot. When an OS is already booted on the machine, it is working ...
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2answers
235 views

Portfast on a trunk port on a Cisco 3750

Good morning everyone! Some history, we have mixed environment of Dell Powerconnect 6248 switches and Cisco 3750 switches and a Cisco 6500 core for our Head office. We have two VLANs 1 & 20 ...
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3answers
86 views

Is grabbing multiple IP addresses from 1 link via a switch a good idea?

I need to connect several machines to the internet for work purposes. However, each workstation only has 1 LAN port. To get around this, I tried to connect a switch to the LAN port to "grab" multiple ...
2
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1answer
329 views

Spanning-tree setup with incompatible switches

I have a set of eight HP ProCurve 2910al-48G Ethernet switches at my datacenter that are set up in a star topology with no physical loops. I want to partially mesh the switches for redundancy and ...
2
votes
2answers
319 views

How to anticipate spanning-tree changes to prevent packet loss during convergence?

We have a LAN with Cisco switches, redundant cabling and spanning tree. If I understand it correctly, when I pull out a redundant cable (that is currently "used" by the spanning tree) it takes several ...
7
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1answer
3k views

Layer 2 Loop Avoidance: Three Switches in Series

I know this seems like a homework question, but it's actually part of a larger project (and network) and need to break it down into chunks so I'm clear with what I'm doing. I've never worked with ...
4
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1answer
121 views

STP in a mixed environment

Good day all, We have some a mixed environment of Dell Powerconnect and Cisco switches. On both brands of switches, I am seeing numerous STP topology changes. I've decided to try on work on the Dell ...
1
vote
2answers
109 views

3 dedicated wires for 3 VLANs between two switches: (M)STP failing

looking for a couple of hints from you we have a small but peculiar networking need: - 3 vlans, that are to be propagated among two L2 switches - we need to partition the vlans as much as possible, ...
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5answers
3k views

If you turn on spanning tree, how do you know there is an issue with your network?

I have been learning about spanning tree protocol (STP/RSTP/MSTP) and was wondering, once I turn it on and it's protecting against for example network loops, how do I know there is a network loop? I ...
2
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1answer
237 views

Intermittent connectivity problems for servers on VLAN 1 with spanning tree

Recently we implemented spanning tree and redundant links in our infrastructure. This has resulted in systems on the default VLAN having intermittent connectivity problems when I plug in the backup ...
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2answers
3k views

HP to Cisco spanning tree root flapping

Per a recent question I recently configured both my HP (2x 2900) and Cisco (1x 3750) hardware to use MSTP for interoperability. I thought this was functional until I applied the change to the third ...
2
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2answers
2k views

Configure spanning tree from HP to Cisco hardware

I have three switches I'd like to configure in a loop - a Cisco stack (3750s) and two HP 2900 series. Each is connected to the next with a 10 gig backplane of one form or another. How do I configure ...
0
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1answer
637 views

Spanning tree outage with root port removal

Today, A tech at a remote server site unplugged a single port from one of our fiber converters for our WAN uplink from a Dell PowerConnect Switch. We lost all networking on the 3 stacked 48 port ...
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2answers
3k views

spanning tree protocol(STP) bridge priority configuration

I'm trying to figure out the appropriate spanning tree protocol settings for a redundant network topology I'm in the process of implementing. The graphic demonstrates what the physical layer will look ...
1
vote
2answers
122 views

Spanning-Tree and redundant links

I have 2 switches which have redundancy between them, meaning fa0/1 on SW1 is connected to fa0/1 on SW2, and fa0/2 on SW1 is connected to fa0/2 on SW2. Both of the switches have the same BID, however ...
1
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1answer
3k views

Spanning Tree Protocol (STP) to prevent network loop back issues?

I have several locations with managed network switches - for example, one being a stack of 3com 4500's. On occasion we have an issue where a user somewhere in the building decides to plug in their ...
0
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1answer
105 views

Strange behavoir of PVST

: The spanning-tree root for vlan 1050(192.168.50.0) is Core2 : The spanning-tree root for vlan 1020(192.168.20.0) is Core1 I was trying to add some redundancy to my network and added the links ...
1
vote
1answer
216 views

Does native vlan tagging work with voice vlan?

we hard-code native vlan tagging: vlan dot1q tag native then we configure a port like this: interface FastEthernet0/1 switchport access vlan 20 switchport mode access switchport voice vlan 500 mls ...
0
votes
1answer
2k views

Netgear GS724T port issue between two switches

We have three 24 port (Gigabit) Netgear GS724T switches which are connected in the following way: SW-003 > SW-001 > SW-002 The port on SW-002 that connects to Sw-003 is constantly ...
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2answers
3k views

Spanning Tree blocking DHCP requests in Windows/BOOTP

We have a LAN with 3 Cisco switches (SLM2048), a handful of Windows Servers and some WinXP/Win7PRO workstations. All devices are on the same LAN, no VLANs, nothing special configured on the switch ...
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3answers
181 views

Stackwise and RSTP states of other uplinks

Assuming I've got four C3750X, each side stacked with Stackwise Plus and using RSTP: C1 -----10Gbit----- C2 | | | | SW SW | | ...
0
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1answer
593 views

For a switch using RSTP (or MSTP) on which port states/roles does it send BPDUs?

In trying to wrap my head around MSTP and RSTP I have read conflicting information about which ports a switch will send BPDUs through. It is clear to me that for MSTP the switch sends the BPDUs needed ...
1
vote
1answer
1k views

SSTP BPDU with bad TLV and macflap — info please

I'm slowly locking down the network I've inherited and mac-flapping has been a problem in the past with customers doing all kinds of crazy things. Thats changing but I am now encountering this error: ...
2
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3answers
296 views

Firewall that supports HighAvailability and Spanning Tree

I'm looking for a firewall appliance that supports high availability and spanning tree. I have two ha-cluster nodes and I'd like to protect them with a firewall. To avoid a single point of failure, ...
0
votes
1answer
4k views

Spanning Tree Portfast in JUNOS

Can someone tell me what the Juniper JUNOS equivalent is for Cisco's spanning tree portfast command? My google-fu keeps leading me to long whitepapers on Spanning tree and not so much configuration ...
1
vote
3answers
2k views

Spanning Tree required/desired for Port-Channel?

I have two Dell PowerConnect switches I want to connect together via Port-Channel links (2 ethernet links). Spanning tree is enabled on both switches, so therefore applied to all interfaces unless ...
3
votes
1answer
189 views

Network topology, clearing congestion

Our networking components consist of (3) x D-Link DGS 1248T Switches, and a router. We have 4-5 servers running as VMWare Host, HTTPD, and Storage. The clients on the network are connected to the ...
3
votes
3answers
1k views

Redundant Ethernet links from a Linux box

This could be an RTFM kind of question. If so, I'll gladly award the answer to whoever gives a link to TFM :) In my racks, I've got redundancy all over the place. Two sets of switches, two upstream ...
5
votes
1answer
505 views

Setting spanning tree link “priorities” in Cisco switches

I've got a pair of C2960G-48 switches (running IOS 12.2(46)SE, if it makes a difference) with redundant trunks in place. On these switches there are a bunch of VLANs that carry quite heavy traffic at ...
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2answers
306 views

Should the 3Com NJ225 switch implement the spanning tree protocol?

We recently purchased some 3Com IntelliJack NJ225 switches: The specification states that they support IEEE 802.1D, and a mandatory part of this standard is support for the rapid spanning tree ...
9
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5answers
1k views

Spanning Tree Setup

I understand the basics of spanning tree, but that's about it. I'm hoping that someone can tell me if this will work as I want it to. I've got two Cisco ACE load ballancers setup for redundancy. ...
2
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8answers
1k views

New MPLS link bringing network to a halt - Spanning Tree Protocol

We have a simple 2 office location network. This was previuosly connected via kilostream connection. This has now been replaced by an MPLS connection using Cisco routers. When we connect the MPLS to ...
3
votes
2answers
1k views

Preventing packet storm on VLAN

I've got a connection in a datacenter where the network provider gives me two Ethernet connections. They're supposedly hooked up to the same VLAN, such that I can wire them up to my switch and only ...