Few More Intraday Trading Tips | Intraday Ep-03 #Money

Stub Flag in EIGRP Hello Packet

How EIGRP Hello packet looks like if it is not having stub flag; picture express best.

Now, how the hello packet will be looking if we include stub command in EIGRP Process. Let's check the same.

So, if you enable stub in EIGRP then you will have one more field in hello packet called "Peer Stub Information" which is 6 bit length information where all the stub option mentioned, you can even see the same in the screenshot. which type of stub is enabled that will be set to "1".

So, this is how the Hello packet being different in EIGRP in respect to with or without Stub flag.

Reducing time of traceroute in Windows System and Cisco Routers

We all know traceroute is the most important troubleshooting tool we required in our day-to-day operation but unfortunately this is one of the slowest tool.

I was aware that this tool is slow only because of domain lookup and we can tweak it to a bit faster, but what I was not aware is that if my organization required domain lookup then how can we reduce the time because at the time of troubleshooting if your traceroute takes 30 secs to respond then it is the most painful situation.

Thanks to my friend Paul Stewart(CCIE#26009) to help me to understand that how to tweak the same.

Please find the ways below through which you can reduce the time of traceroute:

1. In Windows System:

    You can use "-d" attribute to make sure traceroute is not doing the domain lookup. Please find the below Screenshot.

2. In Cisco Router:

    There are two ways through which you can achieve the same, either you stop the IP domain-lookup by         using the command "no ip domain-lookup" or you use the keyword "numeric" at the end of the traceroute     command.

 

Hope, it might helped you. I would like to say thank you to have patience to read my blog.

What are the differences between the Router and Layer 3 Switch

If a device can routes then it is a router. So, you can call Layer-3 Switch as a Switch with Routing Capabilities.

As per my understanding the name Layer-3 Switch is nothing but a marketing term.

Okay, now lets move on to the differences between a Layer-3 Switch and a Router.

A Router can support traditional WAN Links like E1/T1/DS3 over POS interface/ Smart Serial Interface for V.35 etc. whereas Switch can only supports WAN link if it is Ethernet or Fiber Drop.

Modular Switches can support FWSM or ASA Module even Wi-Fi Controllers also.

Again, in compare Router can support Cisco Call Manager Express or ISR G2 routers can support WAVE even.

Usually switches do not support NAT/Netflow or Nbar until you go into a high end Switch like 6500, whereas even small routers can support the same, it is probably because of Router's rugged  IOS.

The forwarding on switches is done on ASIC (Application Specific Integrated Circuits) which is done in hardware rather than a software whereas forwarding on routers are done on software.

Now, these all are technical but at the end of the day you need to decide the positioning according to your business requirement because both will provide you the exit gateway.

Good Luck Guys........I will again come back with some post.

BGP Attributes

There are eleven BGP attributes and are basically two major types of attribute:

1. Well Known
2. Optional

Well Known Attributes:

Well Known attributes are must be recognized by each compliant of BGP implementations. Well Known attributes are propagated to other neighbors also. This can be further divided into:

1. Mandatory:

    It is BGP well known attributes. Mandatory attributes are must be present in all update message passed between BGP peers. It is present in route description. Must be supported and propagated.

There are four attributes under this category are as follows:

    i) Weight:

        Weight is a cisco defined attribute that is local to a router. The weight attribute is not advertised to neighboring routers. If the router learns about more than one route to the same destination, the route with the highest weight is preferred.

   ii) AS Path:
   
        When a route advertisement passes through an autonomous system, the AS number is added to an ordered list of AS numbers that the route advertisement has traversed.

  iii) Origin:

        The origin attribute indicates how BGP learned about a particular route. The origin attribute can have one of three possible values:

        a) IGP:

           The route is interior to the originating AS. This value is set when the network router configuration command is used to inject the route into BGP.

        b) EGP:

           The route is learned via Exterior Gateway Protocol (EGP).

        c) Incomplete:

           The origin of the route is unknown or is learned some other way. An origin of incomplete occurs when a route is redistributed into BGP.
            
   iv) Next-hop:

        The eBGP next-hop attribute is the IP address that is used to reach the advertising router. For eBGP peers, the next-hop address is the IP address of the connection between the peers.

2. Discretionary:

    It is a BGP well Known attributes. Discretionary attributes may be present on update messages. Must be supported but propagation optional.

    There are two attributes under this category are as follows:

    i) Local Preference:

        The local preference attribute is used to prefer an exit point from the local autonomous system. Unlike the weight attribute, the local preference attribute is propagated through-out the local AS. If there are multiple exit points from the AS, the local preference attribute is used to select the exit point for a specific route.

   ii) Atomic Aggregate:

        Notes that route summurization has been performed.

Optional Attributes:

Optional attributes are recognized by some implementation of BGP and expected that not recognized by everyone. Optional attributes are propagated to their neighbor based on the meanings. This can be further divided into:

1. Transitive:

    Optional transitive attributes don't have to be supported, but must be passed onto peers. Marked as partial if unsupported by neighbor.

    There are two attributes under this category are as follows:

    i) Community:

        The community attributes provides a way of grouping destinations, called communities, to which routing decisions (such as acceptance, preference and redistribution) can be applied. Route maps are used to set the community attribute. The predefined community attributes are as follows:
      
       a) No-export:

          Do not advertise this route to eBGP peers.

       b) No-advertise:

          Do not advertise this route to any peers.

       c) Internet:

          Advertise this route to the internet community; all routers in the network belong to it.

    ii) Aggregator:

         Identifies the router and AS where summarization was performed.

2. Non-Transitive:

    Optional non-transitive attributes don't have to be supported, and can be ignored. Deleted if unsupported by neighbor.

    There are three attributes under this category are as follows:

    i) Multi-Exit Discriminator(MED):

       The multi-exit discriminator(MED) or metric attribute is used as a suggestion to an external AS regarding the preferred route into the AS that is advertising the metric.  

   ii) Originator ID:

       The originator ID attribute identifies a route reflector.
  
  iii) Cluster List:
    
       The cluster list attribute records the route reflector clusters the route has traversed.