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Enhanced Interior Gateway Routing Protocol – Scalable EIGRP – Scenario Two

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on September 10, 2008

in BSCI, BSCI Questions, Certification and Cisco Systems

. 0 Comments

Working from the my last couple of EIGRP consists I am going to try and crystallize some of the material found by working through questions found in Stewart, B,D., Gough, C (2008). CCNP BSCI Official Exam Certification Guide, Fourth Edition. Indianapolis: Cisco Press.

The 256 kbps access line to the hub has 56 kbps access lines to each of ten spoke sites. Each link has a Frame Relay Committed Information Rate (COR) of 56 kbps. The access line to each router reflects the CIR. The access line to the hub router, Router A, is 256 kbps, but the CIR of the hub is the same as its access line.

From a Frame relay perspective, a circuit is considered oversubscribed when the sub of the CIRs of the remote circuits is higher than the CIR of the hub location. With ten links, each with a CIR of 56 kbps, this circuit is oversubscribed (56 kbps * 10 = 560 kbps).

How much bandwidth has each circuit been allocated? why was this value chosen by the administrator?
The maximum allowed bandwidth is controlled by the hub (256 kbps) in this hub-and-spoke network, because the maximum total spoke bandwidth is more than the hubs CIR (560 kbps), one cannot allow any individual Permanent Virtual Circuit (PVC) to utilize more than (256 kpbs / 10) 25 kbps at one time.
What bandwidth utilization is available to EIGRP? why was this value chosen by the administrator?
Because not much user data traffic is expected and the data rate is low one can allow EIGRP to use as much as 90% of the bandwidth.
If Router A fails, what would the effect be on the network?
If Router A fails there would be no communication between spoke sites as Router A is the hub. Each individual site would function but WAN connectivity would be lost. Each spoke router will stop receiving Hellos for the Hold time duration (3x Hello) and then and assume that the neighbours are dead. There not being any neighbours to ask for a route,the Topology Table will be updated and the router will send updates out about this change.
Is summarization possible on the routers entering the WAN cloud, or is it possible on the network not shown in the figure that are on the other side of the routers? Give a reason for your answer.
EIGRP allows summarization at the interface level (barring that the addressing scheme is such that it will allow this to happen). This is an advantage of EIGRP over OSPF (OSPF allows summarization only at Area Border Router (ABR))

Resources:

Stewart, B,D., Gough, C (2008). CCNP BSCI Official Exam Certification Guide, Fourth Edition. Indianapolis: Cisco Press.

Notes and Notices:

This is a part of my personal BSCI notes and research to assist myself in learning and understanding the concepts and theory for the BSCI exam. I learn by making notes reading and writing things down and wish to file them where I can’t lose them. These notes are not to be seen, judged or mistaken for replacements to Cisco recognized and authorized training which I personally support and attend and suggest you undertake if you are going for the BSCI Certification.

Enhanced Interior Gateway Routing Protocol – Scalable EIGRP – Scenario One

Published

Deon Botha

on September 10, 2008

in BSCI, BSCI Questions, Certification and Cisco Systems

. 0 Comments

Working from the my last couple of EIGRP posts I am going to try and crystallize some of the material found by working through questions found in Stewart, B,D., Gough, C (2008). CCNP BSCI Official Exam Certification Guide, Fourth Edition. Indianapolis: Cisco Press. The Scenario works from the EIGRP Technology White Paper Sections on Cisco.com

The above network is experiencing timeouts and network crashes. In addition, EIGRP appears to be losing routes from its routing tables, which is adding to the problem.

What changes to addressing or EIGRP could affect the route drops and network problems? State the configuration commands necessary to activate this solution on Router A.
Summarization is the keystone to scalable EIGRP operation. Summarization will limit the query range preventing query scoping. This will also prevent the routes in the Topology Table from being SIA, which affects performance.
Enter Router Mode to Define Routing Protocol RouterA(config)#router eigrp 1 Define EIGRP Network for Routing Protocol RouterA(config-router)#network 10.0.0.0 Disable Auto Summarization RouterA(config-router)#no auto-summary This is me being strange and clean exiting from the routing protocol sub-section RouterA(config-router)#exit Enter the Serial Interface where to start defining your Hub on the Hub-and-Spoke Network RouterA(config)#interface serial 0/0 Define summary for this interface RouterA(config-if)#ip summary-address eigrp 1 10.1.0.0 255.255.0.0 RouterA(config-if)#exit
The WAN is a Frame Relay cloud, and Router A is the hub in the hub-and-spoke configuration. Each Virtual Circuit (VC) is 56-kbps. Give commands to configure Router A for EIGRP over this Non-Broadcast Multi-Access (NBMA) Cloud.
This Cisco.com Configuration Note should explain why the below is done.
RouterA(config)#interface serial 0/0 RouterA(config-if)#frame-relay encapsulation RouterA(config-if)#bandwidth 168 RouterA(config-if)#exit
Give the commands to configure Router B for EIGRP over this NBMA cloud.
RouterA(config)#interface serial 0/0 RouterA(config-if)#frame-relay encapsulation RouterA(config-if)#bandwidth 56 RouterA(config-if)#exit

Resources:

Stewart, B,D., Gough, C (2008). CCNP BSCI Official Exam Certification Guide, Fourth Edition. Indianapolis: Cisco Press.

Notes and Notices:

Enhanced Interior Gateway Routing Protocol – Introduction

Published

Deon Botha

on August 5, 2008

in BSCI, BSCI Notes, Certification, Cisco Systems, Concepts and Constructs and EIGRP

. 2 Comments

This is the Introduction to Enhanced Interior Gateway Routing Protocol (EIGRP) most of this paragraph you will find here; moving swiftly along EIGRP is a Cisco Proprietary distance vector routing protocol that uses the same sophisticated metric that Interior Gateway Routing Protocol (IGRP) uses plus the Diffusing Update Algorithm (DUAL) convergences algorithm for loop-free routing. EIGRP is able to converge quickly and uses little bandwidth (like OSPF) because it separates keepalives, routing information and uses reliable updates. EIGRP is sometimes referred to as a hybrid routing protocol.

EIGRP was created (maybe read modified/updated) to solve scaling limitations that IGRP faced while still keeping the advantages of distance vector routing protocols (simplicity, economy of memory usage, and economy of processor resources). EIGRP is scalable in terms of hardware resources and network capacity. EIGRP is also very quick.

I use British English there will be a few small differences in spelling versus American English (the English Cisco Uses). Example: Neighbour vs Neighbor

Neighbourship and Reliable Incremental Updates

EIGRP supports several routed protocols independently (IP, IPX, Appletalk and IPv6) This means that each routed protocol has a best path that is not shared between other routed protocols.

EIGRP produces reliable (receiver ACKs the transmission was received and understood) updates by identifying its updates using IP protocol 88.

EIGRP uses five (5) types of packets to communicate:

Hello - Identifies neighbours; Hellos sent via multicast periodically and ACK.
Update – Advertises routes. Updates sent as multicast only when there is a change.
ACK – ACK receipt of an update.
Query – Used to ask about routes for which previous best path has been lost.
- If an update indicates that a path down, multicast queries used to ask other neighbours if they still have path.
- If querying router does not receive reply from each of its neighbours, it repeats query as a unicast to each unresponsive neighbour until it either gets a reply or gives up after sixteen (16) attempts.
Reply – Used to answer query. Each neighbour responds to the query with a unicast reply indicating an alternative path or that it does not have a path.

Neighbour Discovery and Recovery

EIGRP uses a reliable update procedure; this creates two problems,

The router needs to know how many other routers exist so that it knows how many ACK to expect.
The router needs to know whether a missing advertisement should be interpreted as “no new information” or “neighbour disconnected”.

EIGRP uses neighbourship to address these problems (periodic hellos).

The first hellos build a list of neighbours (Neighbour Table).
following hellos indicate that the neighbours are still alive.

If hellos are missed (for the period of the hold time) then the neighbour is removed from the EIGRP table and routing reconverges.

The discovery process begins with multicast advertisements being sent out and individual routers replying with unicast ACK. The neighbour table tracks replies to make sure that each neighbour responds. If a neighbour does not respond with an ACK a follow-up unicast message is sent, after 16 times attempts the neighbour is removed from the neighbour table and EIGRP continues with its next task.

Sophisticated Metric

EIGRP uses a sophisticated metric that takes into account bandwidth, load, reliability, and delay. The metric equation is:

EIGRP selects paths based on the fastest path (lowest value). To do that it uses K-values (K1 to K5 in the equation). The K-values are constants(don’t change) that are used to adjust the relative contribution of the various parameters to the total metric. The EIGRP K variables are set as follows:

Bandwidth – 107 kbps divided by the slowest link along the path. Because routing protocols select the lowest metric, inverting bandwidth makes faster paths have lower costs.
Load and reliability – 8-bit calculated values based on the performance of the link. Both are multiplied by a zero K-value (neither used).
Delay – a constant value on every interface type, and is stored in terms of microseconds (serial has a delay of 20,000 microseconds and Ethernet has a delay of 1000 microseconds). EIGRP uses a sum of all delays along the path, in microseconds.

By default:

K1 = K3 = 1 and
K2 = K4 = K5 = 0 (if you followed the maths if K5=0 then the metric equals 0).

Because the metric basically = 0 which will not be useful EIGRP ignores everything outside the parentheses.

Using the default K-values the equation then becomes:

Substituting the earlier description of variables, the equation becomes 10,000,000 divided by the chokepoint (worst/slowest link along the path) bandwidth plus the sum of delays:

Exercise to crystallize

This entire section is so that I understand how EIGRP selects the route using the below diagram (from Brent D, Stewarts CCNP book) lets plug in some values and see it work.

If we want to send traffic from Router A to Router D, which path would be used?

The top path ABCD has a chokepoint bandwidth of 768 Kbps and would go along 3 serial lines and look like this in the equation:

The bottom path AED has a chokepoint bandwidth of 512 Kbps and would go across 2 serial lines and look like this in the equation:

The result is that EIGRP chooses ABCD (top path) based on bandwidth.

Diffusing Update Algorithm (DUAL)

EIGRP uses the Diffusing update Algorithm (DUAL) which is a modification to the way distance-vector routing typically works. DUAL allows routers to identify loop-free failover paths. Using the same graphic as above lets do an exercise and figure out how DUAL works.

How DUAL works is that neighbouring routers advertise costs (using the below diagram. Lets say router A wants to send a packets to Router D). The two costs advertised by neighbours are as follows:

To send a packet from A to D the Advertised Distance (AD) is either via BCD or ED and excludes the first hop.
The other advertised metric is the Feasible Distance (FD) which is to send a packet the total distance ABCD or AED.

The idea that a path through a neighbour is loop free if the neighbour is closer is called the feasibility requirement and can be restated as “using a path where the neighbour’s advertised distance is less than our feasible distance will not result in a loop”.

The neighbour with the best path will be referred to as the successor. Neighbours that meet the feasibility requirements are called feasible successors. In emergencies, EIGRP knows that using feasible successors will not cause routing loops and instantly switches to the backup path.

Using the above diagram again I am going to be trying to reach Router D. What I did was plug in values using the same equation from the above exercise, just using each individual router (A, B, C, E) to get to D.

Queries

Having a Feasible Successor provides the best convergence. A feasible successor is a backup path and can be substituted should the active path go down at any point (without the need to change state and ask neighbours for a path). Should an active path go down and no Feasible Successor exist, a router will send out queries to remaining neighbours. If a neighbour does not know of a an alternative path, it will recursively ask neighbours.

Recursive queries can loop, forcing the router to time-out the query. This is known as stuck in active (SIA). EIGRP uses split horizon (a router should not advertise a network down a link from which it learned about the network – CCNA).

Queries will continue until an answer is found or until no one is left to query. When queries are produced the router changes to an Active State (actively querying for an alternative path) and sets a timer (3 minutes default). If the timer expires before an answer is returned the router is considered SIA. SIA typically occurs because queries are not properly limited to an area.

The primary way to limit how far queries travel (called query scoping) is to summarize (also allows quick convergence).

Incremental Updates

EIGRP periodically sends hellos to maintain neighbourship, but only sends updates when a change occurs. When a route is changed or withdrawn, an incremental update is sent including only those changes.

Multicast Addressing for Updates

EIGRP sends some packets using a reliable transport protocol (RTP). An example would be EIGRP sending a single multicast hello packet with an indicator that says it need not be ACK. Other types of packets like updates indicate that packet ACK is required.

EIGRP uses both multicast and unicast addressing.

Some packets are sent using Real-Time protocol (RTP), a Cisco Proprietary (?? Can’t find a source for this ??) protocol that oversees the communication of EIGRP packets. These packets are sent with sequence numbers to make the transmission of data reliable. Hellos and ACKs do not require acknowledgement.

Incremental Updates cannot be anticipated; update, query, and reply packets must be ACK by the receiving neighbour.

Updates are sent using reliable multicast (Reserved Class D address, 224.0.0.10). When a neighbour receives a multicast, it ACKs the receipt with an unreliable unicast.

Unequal-Cost load sharing

All IP routing protocols on Cisco routers support equal-cost load sharing. EIGRP is unique in its support for unequal-cost load sharing.

Unequal-cost load balancing takes the best FD and multiplies it by variance. Any other path with an FD less than this product (the product of multiplication read answer) is used for load sharing. EIGRP also does proportional unequal-cost load sharing.

EIGRP will pass a relative portion of the traffic to each interface (60/40) allowing links to a destination to be used to carry data without saturating the slower links or limiting the faster links.

Resources:

Stewart, Brent, D. 2008, CCNP BSCI Official Exam Certification Guide, 4th Ed. Indianapolis: Cisco Press.

Have a look at EIGRP Aragoen Celtdra notes on the same section of work

Introduction to EIGRP

Internetworking Technology Handbook – EIGRP

EIGRP Technology Whitepaper

The Dual Algorithm

Notes and Notices:

BSCI IP Foundation – IP Addressing

Published

Deon Botha

on July 29, 2008

in Addressing, BSCI, BSCI Notes, CIDR, Certification, Cisco Systems and Concepts and Constructs

. 0 Comments

IPv4 uses 32-bit numbers that combine a network and a host address. IP addresses are written in four dotted decimal fields. Each number represents a byte (meaning 192 would be a byte cause in decimal its actually made up of 8 bits). The far left bits are the network address because all hosts on this network have addresses that start with that pattern, the right bits are host addresses and each host has a different value.

Resources for IP address Internetworking Technology Handbook: Internet Protocol

Binary Review

IP Addresses are composed of four bytes (8 bits) and in networking binary works one bit at a time from 0000 0000 to 1111 1111 (0 to 2555) IRL networking that’s what you need to know (test are different cause they ask more than just 255). This is a CCNA topic and I filled note pads with examples just to be able to get it as natural as quick as possible, after a while you start remembering 1010 1100 (172) and 1100 0000 (192). The old CCNA Prep Centre (now Cisco Learning Network) had a Java based game to get this into your head where you had to convert Binary to Decimal against the clock. Helped me because its repetition, repetition, repetition.

Classfull Network Ranges

The above network address (192.168.16.2) at the top of the post starts with 192.xxx.xxx.xxx if you didnt have this table to the right here are the steps to find out which network it belongs to.

Step 1: Converting the first byte to binary 1100 0000 (192).

Step 2: You take the first 4 bits and compare them to what you know:

Class A starts with 0,
Class B starts with 10, and
Class C starts with 110.

This means that the address is a Class C address.

This is something that you must just know, get to know the first column and associate that column with the Class on the table above and then the you can figure out the range easily enough (if you are good with memorizing tables just memorize the bits, range and class).

Network Range by Subnet Masks

Subnetting is when you take the assigned network and break it into smaller pieces this can be useful to conserve IP address space (or when I was doing the CCNA I did this to practice on my office network). The book I am using (Brent D. Stewart, CCNP BSCI Official Exam Certification Guide; Fourth Ed.) uses a Truth Table for AND that is really easy to use and master.

Another method would be to use a table, its also not rocket science but means that you don’t actually know how to do this on the fly.

Moving along lets use the AND method and an example. What network does PC 3 belong to with the IP 192.168.5.100 and the subnet mask 255.255.255.224 and what are the usable addresses on this network.

STEP 1: If the mask is given in decimal notation, convert it to CIDR notation (maybe a long way but you going to need the binary in a second anyway).

STEP 2: To determine the network address of the IP address, copy the network bits from the address as shown by the CIDR notation. Fill in the remaining bits with zeros.

STEP 3: The last Address in the range is the broadcast address. To find this out do the following:

STEP 4: The usable network addresses fall between STEP 2 and STEP 3.

STEP 5:To check this subtract the CIDR notation from 32 that’s 32 – 27 (not the other way around cause you going to get a negative number). To determine the “amount” of addresses then plug it into this formula 2n-2 (n = number of host bits).

Resources for Subnet Mask and Classes: Internetworking Technology Handbook IP Address Classes

Summarization

Summarization (route summarization) is a technique used to group IP networks together to minimize IP advertisements. Doing this allows one to hide unimportant details (flapping links) and to simplify the routing process (make better use of router CPU and memory than to process and store routing information). One of the keys to scalable routing is to take large complicated sets of advertisements and reduce them as much as possible (think internet).

Step 1: Write each network in binary

Step 2: Determine the number of bits that match. This gives a single summary that includes all the routes, but may include a range of addresses that is too large (over-summarization)

Step 3: If step 2 unacceptably over-summarizes, start from the first address and add bits to the prefix until a portion of the range is summarizes. Take the remaining addresses and start this process again.

Step 4: Write each network in binary

Step 5: Determine the number of bits that match.

Step 6: Because step 2 did not over-summarize, the process is complete. Answer is 192.168.0.0/21 and 192.168.0.0/23

Address Planning

Summarization is not possible if network numbers are randomly assigned within an organization. When designing a network it is important to keep in mind the requirements for summarization.

Notes and Notices:

WLAN Configuration

Published

Deon Botha

on May 20, 2008

in 802.11, Access Point, BCMSN, Certification, Cisco Systems, Concepts and Constructs and Wireless

. 0 Comments

This brings together all posts regarding WLAN solutions and deals with configuration of the technologies both autonomous access points (AP) and lightweight access points (LAP) with Cisco Wireless LAN Controllers (WLC).

Autonomous Access Points

APs can be configurared using

Cisco IOS Command Line Interface (CLI) via Serial.
Cisco IOS CLI via Telnet or Secure Shell Protocol (SSH).
Using a Web browser.
Using CiscoWorks Wireless LAN Solution Engine (WLSE).

All the above options require an IP Address on the AP except for the config via Serial. To get an IP Address on an AP either use DHCP or CLI via Serial. The IP Address can be found in the following ways:

Checking the DHCP server for the LAN MAC address of the AP.
Using the Serial Console.
Checking the Cisco Discovery Protocol (CDP) table on the next-hop switch or router.
Checking the network map on other access points in the broadcast domain.

Cisco Aironet 1100,1200, and 1300 Series can perform the following functions in a Wireless network:

Access Point
Repeater (nonroot access point)
Brige (nonroot and root) (NB not 1100)
Workgroup bridge
Scanner

Lightweight Access Points

Lets start this by addressing the Wireless LAN Controller (WLC) first, the initial configuration can be done using:

Cisco IOS Command Line Interface (CLI) via Serial.
Using a web-browser via the service port.

The Service port and initial web-browser config is not available on the Cisco 2000 series WLC.

The WLC requires that an IP Address is configured and can be done in the following ways:

Using the web-browser.
Cisco IOS Command Line Interface (CLI) via Serial.
Using the Cisco Wireless Control System (WCS).

Resources and Links

Cisco.com

Notes and Notices:

This is a part of my personal BCMSN notes and research to assist myself in learning and understanding the concepts and theory for the BCMSN exam. I learn by making notes reading and writing things down and wish to file them where I can’t lose them. These notes are not to be seen, judged or mistaken for replacements to Cisco recognized and authorized training which I personally support and attend and suggest you undertake if you are going for the BCMSN Certification.

Logical Hierarchical Network Addressing

Published

Deon Botha

on April 8, 2008

in Addressing, BCMSN, Certification, Cisco Systems, Concepts and Constructs and ECNM

. 0 Comments

Revisiting logical hierarchical network addressing (CCNA) and going into more depth the reason for using a hierarchical addressing scheme is ease of management, ability to summarize routes and reduction of human error.

Linking this back to the ECNM above is a network diagram showing the campus infrastructure model with building access, distribution and core. Using this as a point of departure for addressing we can start using our past knowledge and apply it.

Design Considerations:

Use blocks of contiguous network numbers (4,8,16,32 or 64) and assigning them to access or building distribution areas allows for easy summarization.
At distribution level assign network numbers contiguously out towards the access layer.
A single IP Subnet for a single VLAN as each VLAN is a broadcast domain.
Subnet along the same binary value on all network numbers, avoid Variable Lenght Subnet masks (VLSM).

Application:

Using the above diagram we have 3 buildings with 6 floors or departments in each building. I am not going to waste time by coming up with department names. Naming is going to be AA (Building A; Department A), Bulding AB (Building A; Department B) then BA (Building B; Department A) and so on.

If the following is given as the department needs for IP addressing space:

		USERS			USERS			USERS
A	A	34	B	A	12	C	A	63
A	B	29	B	B	34	C	B	44
A	C	15	B	C	57	C	C	43
A	D	63	B	D	67	C	D	6
A	E	126	B	E	102	C	E	44
A	F	9	B	F	33	C	F	102

After consulting with the enterprise the 10.0.0.0 network is decided (Class A). Now Using the above considerations the decided information and previously learnt considerations from the CCNA this is what is the outcome.

Building Level:

Building A: 10.1.0.0/16 (Class A Address with a Class B Subnet 255.255.0.0 total 65,534 Hosts)

Building B: 10.2.0.0/16 (Class A Address with a Class B Subnet 255.255.0.0 total 65,534 Hosts)

Building C: 10.3.0.0/16 (Class A Address with a Class B Subnet 255.255.0.0 total 65,543 Hosts)

Department Level:

This is Building A Department Level IP Addressing

		SUBNET ADRESS
A	A	10.1.1.0	/24	255.255.255.0
A	B	10.1.2.0	/24	255.255.255.0
A	C	10.1.3.0	/24	255.255.255.0
A	D	10.1.4.0	/24	255.255.255.0
A	E	10.1.5.0	/24	255.255.255.0
A	F	10.1.6.0	/24	255.255.255.0
UNUSED		10.1.7.0 – 10.1.254.0	For Future Growth

This is Building B Department Level IP Addressing

		SUBNET ADRESS
B	A	10.2.1.0	/24	255.255.255.0
B	B	10.2.2.0	/24	255.255.255.0
B	C	10.2.3.0	/24	255.255.255.0
B	D	10.2.4.0	/24	255.255.255.0
B	E	10.2.5.0	/24	255.255.255.0
B	F	10.2.6.0	/24	255.255.255.0
UNUSED		10.2.7.0 – 10.1.254.0	For Future Growth

This is Building C Department Level IP Addressing

		SUBNET ADRESS
C	A	10.3.1.0	/24	255.255.255.0
C	B	10.3.2.0	/24	255.255.255.0
C	C	10.3.3.0	/24	255.255.255.0
C	D	10.3.4.0	/24	255.255.255.0
C	E	10.3.5.0	/24	255.255.255.0
C	F	10.3.6.0	/24	255.255.255.0
UNUSED		10.3.7.0 – 10.1.254.0	For Future Growth

Implementation Considerations:

There are different traffic types on a network that need to be considered before device placement and VLAN assignment.

Network Management traffic may be present on the network; bridge protocol data units (BPDU), Cisco Discovery Protocol (CDP) updates, Simple Network Management Protocol (SNMP) and Remote Monitoring (RMON). Assing a Separate VLAN for this traffic.

IP Telephony has two types of traffic: signalling between end-stations (IP Phone and Call Manager) and the data packets containing the voice conversations. Assing a different VLAN to be able to apply QoS to this traffic.

To go deeper on the topic Cisco Call Manager server need to be accessible throughout the network at all times. Ensure that there are redundant NICs in the publisher and subscriber servers and redundant connections between those NICs and upstream switch. It is as stated above recommended that Voice traffic be on its own VLAN.

Separate Voice and Data VLANs are recommended because:

Address space conservation and voice device protection
QoS trust boundry extension to voice devices
Protection from malicious network attacks
Ease of management and configuration

IP Multicast traffic for IP/TV broadcasts and software configuration software. Switches need to be configured to keep this traffic from flooding devices that did not accept this and Routers need to be configured to only send this data to networks that requested it.

To go deeper on this topic Layer 3 multicast is provided by Protocol Independant Multicast (PIM) routing protocol. The wiring closet control is provided by Internet Group Management Protocol (IGMP) snooping or Cisco Group Management Protocol (CGMP). Because of the large amount of traffic involved when several high-bandwidth multicast streams are provided it is important to control multicast consider the following:

IP Multicast servers may exist within a server farm or be distributed throughout the network.
Select distribution layer switches to act as PIM rendezvous points (PRs) and place them where they are central to the location of the largest distribution of receiving nodes. PRs are used to temporarily connect multicast sources and receivers.

Normal Data traffic from Server Message Block, Netware Core Protocol (NCP), Simple Mail Transfer Protocol (SMTP), Structured Query Language (SQL) and HTTP. May be assigned different priorities in different parts of the network.

Scavenger Class traffic that protocols or patterns that exceed their normal flows. P2P

Use:

When using the above to map VLANs to a network keep the following in mind:

Examine either the new or existing sybnetting scheme and associate a VLAN to each subnet.
Configure inter-vlan routing at the Distribution layer using the MLS.
Make end-user VLANs and subnets local to a specific switch block (unless wireless requires roaming/mobility).

Conclusion:

What one notices is that each building has a leading IP Address indicator of 10.x.0.0/24 with the additional subnet (VLAN) indicator for the department 10.x.x.0/24 making network management easier and identification easier.

An building is summarized using 10.x.0.0/16 and potentially the campus network is summarised as 10.0.0.0/8

Notes and Notices:

Cisco Enterprise Wide Network Models

Published

Deon Botha

on April 3, 2008

in BCMSN, Certification, Cisco Systems and Enterprise Architecture

. 2 Comments

The Enterprise-Wide Architecture is the more specific enterprise level solution design model for the SONA Framework which gears and prepares the enterprise for Cisco IIN Vision.

The materials I have found on this reads like marketing and advertising sales copy and my version I am afraid might not come off much better.

The model focuses on the sites or locations of the enterprise namely campus (i.e. HQ, main building/buildings), data centre (i.e. could also be located at HQ unless farmed out or if you think of Google with their non-descript concrete buildings around the world that house their server), branch (1 or many locations), teleworker (road warrior or home office worker), and WAN/WAN with specific solutions and benefits for each location on implementing the design model.

Also have a look at the ECNM that has a look at a more recent model on this topic; look specifically at the sub-modules or modules and find these locations mentioned there.

Definitions

You will see the term Campus used often, this term I encountered in my CCNA studies and it is carried through further into later studies. A Campus is one or more buildings connected using a LAN infrastructure within the same geographic area.

You will also remember LAN being defined from CCNA studies and this applies to the Campus definition, a LAN is a network of connected devices within a limited geographic area.

This would build onto the Campus definition in a meaningful way. So to join the two terms a Campus as used in these posts wont span the globe (corporation sized wan environment) but be a localized collection of enterprise buildings, that could tie into the corporate wan, or not, but share a limited geographic area.

Think in South African terms the Didata Campus or maybe something like the Innovation Hub. Both Examples have multiple buildings located in close proximity of each other and have connectivity between each building. In international terms Microsoft Redmond Complex and the Googleplex come to mind as prime examples.

I am not saying that these companies use Cisco kit or employ this enterprise wide architecture (DD might being a Cisco Gold Partner but would probably use the ECNM), I am using their campuses as examples to illustrate the definition.

Overview

Cisco provides the enterprise-wide architecture which supports integration of the entire enterprise network (campus, data centre, WAN, branches, and teleworkers). This helps enterprises protect data and information securely and grow infrastructure and offerings by allowing employees, partners, suppliers, and customers secure, any time and anywhere access to tools, resources and services when needed as they need it.

Campus

Cisco Enterprise Campus Architecture empowers employees with advanced services (end-to-end) by combining core infrastructure (intelligent routing and switching) with tightly integrated productivity-enhancing technologies (IP Communications, Mobility, advanced services). This strategy allows enterprise to increase revenue, productivity, and customer satisfaction.

The design provides for high availability (resilient multilayer design), optimized bandwidth consumption (multicast), and quality of service (QoS) (multicast) while still addressing security challenges like worms, viruses, and other attacks on the network, even at the port level. This is done by a multilayered approach to design and implementation.

The architectural model is standards based thereby extending support on the network for additions like 802.1x and Extensible Authentication Protocol (EAP), IP Security (IPSec), Multi protocol Label Switching Virtual Private Networks (MPLS VPN), identity management, and Virtual Local Area Networks (VLANs).

Data Centre

The Cisco Enterprise Data Centre Architecture supports the need for operational efficiency, optimization of utilization while enabling innovative service-orientated architectures, virtualization, and on-demand computing that is found within enterprise. This architecture model allows the data centre to scale without large or wholesale infrastructural change.

Branch

The Cisco enterprise Branch Architecture grants enterprise/corporate headquarters (HQ) the ability to extend applications and services (security, IP Communication, ERP, etc) to numerous (1 or 100s) of remote locations. The Cisco Empowered Branch solutions set makes use of the Integrated Services Routers (ISR) product range that includes single device integrated security, network analysis, caching, switching, converged voice and video.*

*With every benefit comes setbacks and in this case combining multiple solutions into a single chassis either fixed or modular comes single point of failure.

Teleworker

The Cisco enterprise Teleworker Architecture allows enterprise to deliver secure any time access to remote small or home office employees over standard broadband access services (ADSL, Wireless DSL, and at a stretch HSDPA & EDGE cellular technologies). This provides business with real time constant uptime allowing access to information when needed by employees ( i.e. resiliency) while allowing for a flexible work environment. Through the use of the integrated security within the ISR platform (800 Series) corporate (i.e. campus) security policies are extended to the network edge while enabling converged network services and applications (i.e. IP Telephony*, ERP solutions, etc) reach into employees homes and small offices.

*Check latency and lag issues of Wireless solutions before trying voice on them. Classic case of try before you buy, and try for a while before mind you if it works today doesn’t mean it will work at the end and beginning of the month.

WAN and MAN

The Cisco WAN and MAN Architecture allows for the convergence of voice, video and data service over a single IP network.

Resources:

Enterprise Architecture

Have a look at Aragoen Celtdra website on this topic (its for the BSCI but still applies).

Notes and Notices:

Network Ninja

Tag Archive for 'Addressing'

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Enhanced Interior Gateway Routing Protocol – Scalable EIGRP – Scenario One

Enhanced Interior Gateway Routing Protocol – Introduction

BSCI IP Foundation – IP Addressing

WLAN Configuration

Logical Hierarchical Network Addressing

Cisco Enterprise Wide Network Models

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