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1500 questions
7
votes
1 answer
VTP V3 Cisco Switch Error when creating new VLAN
While trying to create a new VLAN on a switch stack (that has many VLANs and many interconnected switches) I get an error about the switch not being the primary server for VLAN database. When running the exec command "show VTP status" the switch…
Ejoso
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7
votes
1 answer
Why does export/import policy addition/removal cause a BGP session reset?
I was adding a new policy to both import and export list for BGP. Then I observed a bgp session reset. Can anyone explain this for me?
The only change I made was to prepend a new policy to reject everything advertised from the neighbor and advertise…
Bo Cao
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7
votes
3 answers
Why can a packet sniffer in an Ethernet LAN obtain all packets sent over the LAN?
Why can a packet sniffer in an Ethernet LAN obtain all packets sent over the LAN?
In a limited broadcast environment, such as in many Ethernet LANs, a packet sniffer can obtain all packets sent over the LAN.
We know if there is a Wi-Fi network, we…
244boy
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7
votes
2 answers
What precisely is a link?
When reading about layer 2 the word "link" is frequently used but strangely I'm struggling to find a formal definition of it. What is the precise definition of a link?
So in the image below, how many links are in this network and what makes that the…
Isaac
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7
votes
5 answers
Why does the Cisco show run command not show the full version, while the show version command does?
Is there any reason why Cisco show run does not show the full version which is 16.3.7 in this example?
IOSSW#show running-config | include ersion
version 16.3
while show version does?
IOSSW#show version
...
Switch Ports Model SW…
user11392987
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7
votes
1 answer
How to get ipfix working with openvswitch?
I'm trying to monitor my OpenVswitch via IPFix. But I'm banging my head against a brick wall for two days now :/
According to the ovs-vsctl manpage I need to add a new entry into the config-database, more precisely into the "ipfix"-table. That…
Christoph Haefner
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7
votes
2 answers
What exact does MIB represent in SNMP? How is it different from OID?
In SNMP, we represent each entity of information using object and to identify each object uniquely, we use OID (Object Identifier).
Now there is another terminology - MIB. I know it stands for "Management Information Base". However, I am not able to…
Deepak
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7
votes
2 answers
Why Don’t Probe Requests for Specific SSIDs include BSSIDs
I'm looking at WLAN traffic captured from wireshark on monitor mode and notice that out of the 67,000 probe requests, 99.08% have the destination set to FF:FF:FF:FF:FF:FF (Broadcast).
The thing is, it appears as though a substantial chunk of those…
JHAWN
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7
votes
1 answer
MSTP and Rapid-PVST+
We have a medium sized network running all Juniper except for one building. This building is shared with another group, and is completely Cisco. We just trunk our VLANs up there.
Our Juniper network is configured with MSTP with all VLANs belonging…
ZaZa
- 73
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7
votes
4 answers
Can throughput exceed the bandwidth of a network
I took an introductory course to networking this semester and I was wondering:
looking at things at the layer 4 level using TCP can the throughput on the network exceed its bandwidth? According to the definition I believe throughput is defined as…
crommy
- 173
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7
votes
1 answer
Is it possible to use single MAC address for multiple IPv4 addresses?
Topology: modem with router and Ethernet LAN bridge <---> server having one NIC.
Server network interface: It is capable of handling more than one IPv4 address. All addresses are within the same subnetwork.
Modem: Does the routing service and…
user2964971
- 850
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7
votes
2 answers
How do routers on the backbone avoid IP address conflicts?
As the title suggests, how do ISPs, and other networks connected to the backbone ensure that their host network address isn't already in use by another backbone node, as there is no controlling device that governs them?
Jack_Hu
- 173
- 4
7
votes
2 answers
Where is the traffic going?
Here is a routing puzzle:
I'm working on a poorly documented network, and I'm trying to document things as I discover them.
R1 is a core L3 switch. R2 is a router. The FW is a, well, firewall.
On R1, I see traffic (about 1Mbps) in and out on vlan…
Ron Trunk
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7
votes
0 answers
Maximum number of subscribers per FPC in Juniper MX
If link with subscribers, containing about 12000 clients, goes down. One aggregated ethernet containing two links which goes to two different FPC's.
All clients try to authorize on JuniperMX with the help of DHCP Discover messages. This is eoip…
Tomato
- 123
- 9
7
votes
2 answers
Netflow differences between IOS 12.2 and 15.1
Has anyone upgraded their cisco routers from 12.2 to 15.1? I'm curious to know what kind of changes were made to netflow. Most specifically, I'd like to know how (if at all) the CPU utilization changed. The router in question is a 6506-E with a…
SmarterThanOli
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