Hi everybody,   Is there any standard or usual way to configure  LAN equipment to put NMS packets in high priority?  Base on RFC 4594, network control packets or telephony packets could have the highest priority among different classes. NMS is responsible for configuring network equipment through different methods, i.e by SSH or SNMP or even HTTPS. How to make these packets have high priority? 1- By defining an ACL which sperate packets whose destination or source IP address is NMS IP address and the set a high priority DSCP value for them during classification or 2- By defining an ACL which sperate packets whose destination or source MAC address is NMS MAC address and the set a high priority DSCP value for them during classification or 3- Any other way??   your help is greatly appreciated! ... View more

Hi, everyone! it seems that RSTP doesn't care to timers like max_age or forwarding when there is no STP device in a network. The below link approves this: https://community.cisco.com/t5/switching/msg-age-and-max-age-in-rstp/td-p/2251614   So there is no limitation in hop count when we have RSTP in a network?    ... View more

Hi, everybody!   I have designed a network and a part of it has a loop consisting of five SF300 switches. There is an NMS PC at another side of the network. I configure router and switches correctly and I can ping any host connected to SF300 switches without any problem. But when I  ping five SF300 switches, their behavior to the NMS ping is wired. Randomly some of them don't respond to the ping and NMS gets "request time out" or "destination host unreachable ". And the combination of switches which do not respond to the NMS ping, change once in while. For example, sometimes just switch 1 is out of NMS's reach and after a little while without any change in topology or configurations switch 1 becomes normal and then switch 2 and switch 3 don't respond to NMS ping. I have tested Both STP and RSTP and nothing has changed. Also, I disable STP on 4 switches and let one of them handle spanning tree in the loop..... the result was the same. there were three conditions in which switches' behavior get normal: 1- When switch 4 doesn't respond to the NMS ping, for instance, if I connect to the switch 4 CLI directly by a laptop and ping the NMS PC, everything gets back OK and NMS can ping switch 4 again. 2- When there is just one SF300 switch in the loop. 3- When there is no loop. These three pieces of evidence and the fact that there is no problem to pinging a host (which is connected to an unresponding switch) bring to my mind that maybe SF300 has a defect in its management plane to respond to ping. So... does anyone have any experience or idea about my problem? Thank you all, Amir ... View more

Hi everybody!   I have a topology in which there is the main ring and some nodes in the main ring have a minor ring. (see attachment please) 1- which STP configuration has the fastest convergence time? How would you configure spanning tree for all switches? I think RSTP does the best, but Is there any other configuration to help convergence time? 2 - Does RSTP have any limitation? limitation In number of switches for instance? or incompatibility with other vendor's RSTP or spanning tree algorithm? 3- Is RSTP practical solution for this topology with a large number of switches? 45 switches as the main ring and more than 100 switches in minor rings? 4- Is there any other faster way, rather than spanning tree, to provide protection for this large network?    Thank you all!  ... View more

Hi,   I have an SF300 switch and I'm trying to learn QoS by testing and configuring different QoS settings. There are 4 egress queues per each port. When I set the scheduler policy to weighted round robin (instead of strict priority mode) and test 2 sets of weights for egress ports, which are relatively equal, I see different results! For instance, I set weights 1,1,1,3  for queues in the first scenario and the egress queues' packets are coming out of port, likely respecting weights. But in the second scenario when I change the weights  into 3,3,3 and 9, without changing anything else, the egress direction of the port does not behave in compliance with the weights( the 4th queue, with the 9 weight in the second scenario, gets lower share  rather than first scenario)    Is it normal to see this behavior from SF300 switch?   Best, Amir   ... View more

Hi everyone!   I have an SF300 series switch which functions properly in mapping packet to egress queues by CoS value. My test scenario was this: I put one FastEthernet port and one GigabitEthernet port in One VLAN, then I sent two streams of data on Gigabit port, one with CoS=7 and another with CoS=0, each stream has 60 Mbps rate. Then I monitor FastEthernet port which has 100 Mbps bandwidth. the stream with CoS =7 was delivered completely without packet drop( 60 Mbps), but the second stream had packet drop(40 Mbps received)...So the switch is ok in the mapping of CoS to egress queues, but when I did this test by DSCP=46 and DSC=0, the switch behaves two streams equally with the same packet drop.Qo   I don't know where is the problem. The Switch explicitly says it supports DSCP to queues mapping. Could you please help?     here are some configurations:     qos advanced-mode trust dscp Dscp-queue map: d1 : d2 0 1 2 3 4 5 6 7 8 9 ------------------------------------- 0 : 01 01 01 01 01 01 01 01 01 01 1 : 01 01 01 01 01 01 02 02 02 02 2 : 02 02 02 02 03 03 03 03 03 03 3 : 03 03 03 03 03 03 03 03 03 03 4 : 04 04 04 04 04 04 04 04 03 03 5 : 03 03 03 03 03 03 03 03 03 03 6 : 03 03 03 03   ... View more

Hi, everybody!   I'm admin of a LAN and now I'm supposed to configure routing on it. I can define some VLANs on the network and also configure inter-VLAN routing between them(by SVIs or router on a stick). But when I associate each VLAN a subnet, what is the necessity of defining VLANs? Without VLANs, there are some subnets and I configure standard routing, like OSPF, between them and subnets, are separated from each other(like VLANs). So I can't recognize whether to use VLAN-based design or another. Could you please help me with this?   Best, Amir   ... View more