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1500 questions
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4 answers

Which specs should I look for (or avoid) when searching for a iSCSI 10Gbit ethernet switch, independent of brand?

I've been tasked with selecting two new switches intended to be our new iSCSI SAN backbone. Currently, we are using two Dell N4064 improvised for the task since that's what we had when the need arrived, but now we are going to replace them with two…
ÜM Mineiro
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1 answer

ASA5505 and IPv6 over a PPPoE Link

I see a lot of conflicting information about whether or not a Cisco ASA (5505 in this case) can use IPv6 over a PPPoE connection. I see official Cisco documentation making it look easy, but I see plenty of forum posts stating that it doesn't…
Mark Henderson
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1 answer

Cisco ISR G2 encrypted bandwidth restriction?

I have been having complaints of a "slow connection" from several new remote sites. The sites are connected via an MPLS L3VPN service into Cisco 2921's, and we are using Cisco GET-VPN to encrypt the traffic between our locations. All locations…
Brett Lykins
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12
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1 answer

Mac / CAM entries from non-Cisco switches with Q-BRIDGE-MIB

How do I do community string Indexing for other switches like D link DES 3526 and Brocade Fastiron SX800? I am running a java program to poll a specific vlan on a Brocade sx 800 l3 switch. The program throws a "Time out error". I then checked the…
Abhishek Balaji R
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12
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4 answers

Can anyone explain to me the difference between the PSH and URG flags in TCP segment?

According to me when PSH flag is set, it indicates that data will have to be sent immediately to the wire and on receiving side the data has to be pushed to the application immediately. When URG flag is set it indicates that urgent data has to be…
user10433098
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12
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2 answers

Why maximum length of IP, TCP, UDP packet is not suit?

From many tutorials, I get follow knowledge(maybe I'm misunderstood) : maximum of an Ethernet packet is about 1500 bytes. maximum of an IP packet is about 65535 bytes. maximum of a UDP packet is 65515 bytes But when I made a test and watch…
Shuai Li
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12
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8 answers

Using sound waves in layer 1

Is it possible, in theory, to use sound waves as the physical medium to transmit data over a network? In other words, could you implement layer 1 of the OSI networking model using sound waves or am I totally misunderstanding the physics/networking…
driangle
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1 answer

What is the "NDE" interface on a Cisco 6500?

I have a pair of Cisco 6509 routers, which are monitored via SNMP (with Observium, to be accurate). Today we spotted a peak of CPU usage for a Switching Processor. The peak can be correlated with a peak of inbound unicast on a port named…
Benjamin A.
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3 answers

Does Switch need its own MAC address?

I saw a post say Switch do not need its MAC address, unless it's an administrable Switch for managing. but I found the spanning-tree protocol need a MAC address of Switch to form STP Root Bridge ID. so, is the switch always need a MAC address?…
three-blocks
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1 answer

Is it possible to connect two private eBGP peers with the same AS number?

The Problem A third party has implemented a small network and private BGP setup within one of our branches. We need to setup a eBGP peer relationship with this network. However we are both using the same private BGP AS number. The Solution One of…
S.Richmond
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1 answer

After TCP is established which BGP peer will send open message first?

After a Tcp connection is established between two bgp peers. which peer will send the open message first ? the active peer(which is initiating outbound connection) or the passive peer?(peer which is accepting a inbound connection). Or is it…
Hemanth
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12
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3 answers

ALU interop GRE tunnel

I've been trying to figure out how to setup a GRE tunnel between an ALU 7750SR and a 3rd party vendor. I think it's balking at the VC-ID in the SDP but i'm hoping someone has experience getting a GRE tunnel to come up in a multi-vendor environment…
Mud
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12
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1 answer

Why can't we find Ethernet checksum in Wireshark?

I am having a small question regarding Ethernet Frame Header Length. As per my knowledge Ethernet Header size is 18 bytes without VLAN tag and 22 bytes if there is a VLAN tag. But in Wireshark capture I am getting only 14 bytes without VLAN tag and…
user2720323
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4 answers

What are the reasons for seeing an incomplete ARP?

As was mentioned in this post: The reason for seeing an incomplete ARP is that "An ARP request was sent for that address, but the host with that address is not up and running on the LAN, so there is no reply" So, if a multilayer switch sends an ARP…
kamokoba
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12
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2 answers

VXLAN vs VLAN over layer 3

I read that one of the benefits of VXLAN over VLAN is that it can spawn across WAN and multiple layer 3 networks by creating overlay layer 2 networks. However AFAIN VLAN can also do the same using MPLS VPN, L2TPv3 or GRE tunnels, or by trunking and…
mart
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