23
votes
Why are rings not a favorite option in IT networks?
Historically, there were several competing technologies using ring structures like Token Ring or FDDI, but due to higher cost, lower performance, or simply slower development they've all vanished.
...
- 81.5k
20
votes
Why are rings not a favorite option in IT networks?
The downside with ring networks as opposed to for example star networks, is that in a ring topology, any link in the ring needs to have enough capacity for all nodes on that ring, in order to be able ...
- 17k
15
votes
Accepted
5 nines, how is it built from 4 nines links
4 nines = 99.99 %.
That means the probability that a link fail is 0.01 % or 0.0001 in terms of probability (scale 0 - 1).
Assuming independence, The probability that both link fails is 0.0001 x 0....
- 19.4k
14
votes
5 nines, how is it built from 4 nines links
A link that is 99.99% reliable is down 0.01% or 0.0001 of the time. So if the downtime of the two links is independent then both lines will be simultaneously down 0.00000001 of the time. Your link is ...
- 13k
9
votes
I have a single ethernet switch. Should I use spanning tree?
To add to Zac67's and JFL's answers:
In case you decide to enable spanning-tree on the single switch, don't forget to configure the client's and server's switchports as Edge Ports (Cisco speak; ...
- 8,674
9
votes
Why are rings not a favorite option in IT networks?
Historically, we did use ring topologies - e.g. token ring.
It didn't have redundancy. Whenever the ring broke, the whole network went down.
Bus topologies (Ethernet over coaxial) were a bit better in ...
- 259
7
votes
Will STP lose data whilst switching from a failed link?
If i remember, default spanning tree (802.1d) takes about 50 secs to reconverge. That is the duration for which you will be losing frames.
A link is detected down by the loss of 10 hello pkts. These ...
- 585
6
votes
Accepted
Will STP lose data whilst switching from a failed link?
It is possible, even likely, that at least one (probably more) frames will be lost on any failover.
The speed of the failover is highly dependent on what type of redundancy you are using. Spanning ...
- 98.3k
6
votes
Accepted
How does STP convergence work?
I don't understand how a bridge decides that it is not connected to
another bridge performing STP.
If it doesn't hear BPDUs, then there's no bridge connected.
How long will it until it decides ...
- 66.9k
6
votes
Accepted
Network Redundancy with LACP Trunking
Scenario A: Switch 1 has ports 1+2 trunked together via LACP. They are
plugged into Switch 2 ports 1+2.
Both links will be used, but a single flow will only use one link. There is a hashing ...
- 98.3k
6
votes
I have a single ethernet switch. Should I use spanning tree?
As explained by Zac67 answer STP is normally only useful when connecting several switches together.
However there's other related features than can be useful on a standalone switch.
BPDU Guard will ...
- 19.4k
6
votes
Why are rings not a favorite option in IT networks?
I mean it's a great way of providing redundancy with low cost.
That is true if and only if multiple faults don't happen at the same time and one fault is fixed before the next fault happens.
...
- 13k
5
votes
Accepted
Network Ten LTE Hubs Into One Network
If you have access to 10 layer 3 switches you can certainly make this work. Treat each trailer as if it is a campus building with local internet. choose the trailer with the NAS as the core of the ...
- 311
5
votes
Accepted
Is it bad practice to use a Virtual Router for NTP-Clustering?
I can see a few ways of doing this:
Round robin DNS with multiple A records (as suggested in comments by JFL). This would require the clients to properly re-look up the addresses when required, and ...
- 16.1k
5
votes
PVST + MST + RSTP network. Possible to make it work?
Generally, you should stick to one spanning-tree protocol or only use those that interact well (e.g. MSTP and RSTP). Given the 1810 can only run RSTP that would be your choice. The downside of RSTP is ...
- 81.5k
5
votes
I have a single ethernet switch. Should I use spanning tree?
STP protects your network in case two switch ports are connected together, so you should use it generally.
With a single switch, you can have redundant links to an appropriately configured host. ...
- 81.5k
4
votes
Reduce ARP cache time-out?
I have personally done that ARP timeout set to 60 sec for a single VLAN caused 0.05% ARP usage on cisco 29XX series. It is running like that for over a month. No problems at all. Still I'd not ...
- 651
4
votes
Network redundancy design question with BGP
How should i perform failover link using BGP with same ISP?
Form the BGP neighborship loopback interface. As per this thread:
The use of a loopback interface ensures that the neighbor stays up ...
- 2,337
4
votes
Accepted
Network redundancy with low cost switches in a ring
As long as your "expensive" switch runs Spanning Tree Protocol, you can connect your switches in a ring. STP will prevent packet storms by only allowing packets out one of its (ring) ports. But if ...
- 66.9k
4
votes
Connect two routers to a single uplink for full redundancy
I have a single uplink with my ISP at a data center. I have 2 routers
(CISCO 3850). How do I connect these routers to that uplink WITHOUT a
network switch? That switch will be a single point of ...
- 98.3k
4
votes
Network Ten LTE Hubs Into One Network
Two ideas...
I think the typical way to handle it would be a router in every trailer with three subnets: one goes to a switch for a trailer LAN, one goes to a campus backbone LAN for access to ...
- 371
4
votes
Accepted
4507r Supervisor engines aren't operating redundantly
Redundancy on these Catalyst platforms operates in two modes: RPR (Route Processor Redundancy) and SSO (Stateful Switchover).
In RPR mode, the Standby boots up "partially". When the Active dies for ...
- 2,406
4
votes
Network Redundancy with LACP Trunking
From a functional point of view, there's no difference between LACP trunks and static trunks. All links are aggregated (with the limitations Ron has already pointed out) and the aggregation group is ...
- 81.5k
3
votes
Accepted
Load balancing between multiple layer 3 switches
Actually if your access switches connected to the so called "core switches" have just one uplink, either to the HP or to the Juniper, full redundancy is not an option given your constraints of no ...
- 266
3
votes
Accepted
BGP VPN created, how do I give access to internet
There are a few different ways to achieve what you are after. In my experience the easiest way to do this is to use vlans between the Service Provider "PE" router and the Customer "CE" router. One ...
- 661
3
votes
Accepted
Adding a switch to provide redundancy
Do you have enough router ports available to do this ?
You would still have your five trunks between the two buildings, but an outage on SW1 wouldn't bring down the whole LAN anymore.
You would need ...
- 311
3
votes
Accepted
Redundancy in Internet core and edge networks - redundant devices and redundant links
This would be entirely up to the Tier 1 and their strategy/business model and each one may handle this differently. Redundancy is about preventing loss of service first and preventing degradation of ...
- 27.2k
3
votes
Fault tolerance with 3 routers in Packet Tracer
The simplest solution would be to add a dynamic routing protocol such as RIP, EIGRP or OSPF. Then raise the Administrative Distance of the static routes so the dynamically learned routes are ...
- 1,241
3
votes
Accepted
ASA Redendent Failover and stateful link issue
"Everything working good but when i remove g0/6 cable..." --> Does this mean failover is working for you when g0/6 cable is plugged? Please plug back the cable and run the commands show failover and ...
- 3,754
Only top scored, non community-wiki answers of a minimum length are eligible