The Network Management Problem Chapter 3 Network Management

The Network Management Problem Chapter 3 Network Management, MIBs, and MPLS Stephen B. Morris Rodrigo Iglesias de Aliaga Revised Spring 2006 Rudimentary NMS Software Components 1

Overview n n n Network Operators problems with the growth of traffic types and volumes. Operational increase due to Multiple NMS growth. There is a strong need to reduce the cost of ownership and improve the return on investment (ROI) for network equipment. Revised Spring 2006 Rudimentary NMS Software Components 2

Overview n Automated, flow-through actions are required for network management operations. n n n Provisioning Detecting faults Checking (and verifying) performance Billing/accounting Initiating repairs or network upgrades Maintaining the network inventory Revised Spring 2006 Rudimentary NMS Software Components 3

Bringing the Managed Data to the Code n n n Managed objects reside on many SNMP agent hosts. Copies of managed objects reside on SNMP management systems. Changes in agent data may have to be regularly reconciled with the management system copy. Revised Spring 2006 Rudimentary NMS Software Components 4

Bringing the Managed Data to the Code n Components of an NMS Revised Spring 2006 Rudimentary NMS Software Components 5

Bringing the Managed Data to the Code n n The Quality of an NMS is inversely proportional to the gap between its picture of the network and the actual state of the underlying network- the smaller the gap, the better the NMS. As managed NES become more complex, an extra burden is placed on the management system. Revised Spring 2006 Rudimentary NMS Software Components 6

Scalability n Today’s Network is Tomorrow’s NE n n Scalability is one of the biggest problems facing modern networking. A scalability problem occurs when an increase in the number of instances of a given managed object in the network necessitates a compensating, proportional resource increase inside the management system. Revised Spring 2006 Rudimentary NMS Software Components 7

Layer 2 VPN Scalability n n Scalability Problems tend to arise in situations of proportional growth. The N 2 Problem n n n When the number of layer 2 virtual circuits required is proportional to the square of the number of sites. Anything in networking that grows at the rate of N 2 tends to give rise to a problem of scale. As the number of sites gets bigger, the N 2 term is more significant than the other terms. Revised Spring 2006 Rudimentary NMS Software Components 8

The N 2 problem Revised Spring 2006 Rudimentary NMS Software Components 9

The N 2 problem n Layer 3 VPNs n n Layer 3 VPNs provide a much more scalable solution because the number of connections required is proportional to a number of sites, not the square of the number of sites. Layer 3 VPNs avoid the need for a full mesh between all of the customer edge routers by providing these features: n n n A layer 3 core Overlapping IP address range across the connected sites (if separate organizations use the same VPN service) Multiple routing table instances in the provider edge routers Revised Spring 2006 Rudimentary NMS Software Components 10

Virtual Circuit Status Monitoring n Scalability problems arise when the MIB table entries become very large due to NMS attempts to read all MIB table entries at the same time. Revised Spring 2006 Rudimentary NMS Software Components 11

MIB Scalability n Network operators and their users demand more: n n Bandwidth Faster Networks Bigger Devices Scalability concerns are growing because routers and switches are routinely expected to support the creation of millions of virtual circuits. Revised Spring 2006 Rudimentary NMS Software Components 12

Creating LSPs in an MPLS network Revised Spring 2006 Rudimentary NMS Software Components 13

Other Enterprise Network Scalability Issues n Scalability concerns also affect enterprise networks in these areas: n Storage Solutions n n Administration of Firewalls n n Access control lists and static routes Security Managements n n Rules for permitting or blocking packet transit Routers n n Adding, deleting, modifying, and monitoring SANs Encryption keys, biometrics facilities, and password control Application Management Revised Spring 2006 Rudimentary NMS Software Components 14

Light Reading Trials n Internet core routers from Cisco, Juniper, Charlotte’s Networks, and Foundry Networks were stress-tested during 2001 using these tests n n MPLS throughput Latency IP throughput at OC-48 IP throughput at OC-192 Revised Spring 2006 Rudimentary NMS Software Components 15

Large NEs n Advantages of the deployment of much bigger device n n They reduce the number of devices required, saving central office (CO) space and reducing cooling and power requirements. They may help to reduce cabling by aggregating links. They offer richer feature set. Disadvantages n n n They are harder to manage. They potentially generate vast amounts of management data. They are a possible single point of failure if not back up. Revised Spring 2006 Rudimentary NMS Software Components 16

Expensive (and Scarce) Development Skill Sets n n n Building management systems for the devices of today and tomorrow is increasingly difficult. General migration to a Layer 3 infrastructure is another reason for the widening gap between available development skills and required product features. The need for customers to see rapid ROI for all infrastructural purchases Revised Spring 2006 Rudimentary NMS Software Components 17

Expensive (and Scarce) Development Skill Sets n n A different approach is needed for developing management systems. Acquiring skills like these would positively enhance the development process. n n n n A solution mindset Distributed, creative problem solving Taking ownership Acquiring domain expertise Embracing short development cycles Minimizing code changes Strong testing capability Revised Spring 2006 Rudimentary NMS Software Components 18

A Solution Mindset n Solutions have a number of characteristics n n n Clear economic value Fulfillment of important requirements Resolution of one or more end-user problems Revised Spring 2006 Rudimentary NMS Software Components 19

A Solution Mindset Revised Spring 2006 Rudimentary NMS Software Components 20

Distributed, Creative Problem Solving n n n Software Bugs NE Bugs (Hard to identify) Performance Bottlenecks in FCAPS applications due to congestion on the network. Client Applications crashing from time to time MIB Table Corruption SNMP Agent Exceptions Revised Spring 2006 Rudimentary NMS Software Components 21

Distributed, Creative Problem Solving n Tools available to solve these problems n n UML support packages Java/C++/SDL products Version control Debuggers Revised Spring 2006 Rudimentary NMS Software Components 22

Taking Ownership n n A broad task can be ring-fenced by a small group of developers who take responsibility for design, development, and delivery. Traditional development boundaries are removed. n n n No more pure GUI, backend, or database developers. All NMS software developers should strive to extend their portfolio of skills to achieve this. Institutional memory relates to individual developers with key knowledge of product infrastructure. Revised Spring 2006 Rudimentary NMS Software Components 23

Acquiring Domain Expertise n Domain expertise represents a range of detailed knowledge n IP/MPLS that can be readily applied to the needs of an organization. Revised Spring 2006 Rudimentary NMS Software Components 24

Acquiring Domain Expertise n Knowledge include areas such us: n n n Layer 2 and layer 3 traffic engineering Layer 2 and layer 3 Qo. S Network Management Convergence of legacy technologies into IP Backward and forward compatibility of new technologies n MPLS Revised Spring 2006 Rudimentary NMS Software Components 25

Linked Overviews n n ATM Linked Overview IP Linked Overview Embracing Short Development Cycles Minimizing Code Changes Revised Spring 2006 Rudimentary NMS Software Components 26

Elements of NMS Development n NMS Developments n n n Using a browser-based GUI Developer wants to check that the software executed the correct actions During provisioning, developer verifies Java Database is updated by the management system code Verifying that the correct set of managed objects was written to the NE Revised Spring 2006 Rudimentary NMS Software Components 27

Elements of NMS Development n n n n Data Analysis Upgrade considerations UML, Java, and Object-Oriented Development Class Design for Major NMS Features GUI Development Middleware Using CORBA-Based Products Insulating Applications from Low-Level Code Revised Spring 2006 Rudimentary NMS Software Components 28

Expensive (and Scarce) Operational Skill Sets n n The growing complexity of networks is pointing to increasingly scarce operational skills Multiservice Switches n Enterprise network typically want to: n n n Reduce the payback period for new purchases Maintain and expand existing network services Reduce operational costs associated with multiple networks n n Telephony LAN Revised Spring 2006 Rudimentary NMS Software Components 29

Expensive (and Scarce) Operational Skill Sets n Multiservice Switches n MPLS provides a way of filling these needs in conjunction with multiservice switches n n ATM FR TDM IP Revised Spring 2006 Rudimentary NMS Software Components 30

MPLS: Second Chunk n Managed objects of MPLS n n n Explicit Route Objects Resource blocks Tunnels and LSPs In-segments Out-segments Cross-connects Routing Protocols Signaling Protocols Label operations Traffic Engineering Qo. S Revised Spring 2006 Rudimentary NMS Software Components 31

Explicit Route Objects n n n An ERO is a of layer 3 address hops inside an MPLS cloud Describes a list of MPLS nodes through which a tunnel passes. EROs are used by signaling protocols to create tunnels Revised Spring 2006 Rudimentary NMS Software Components 32

Resource Blocks n n n MPLS permits the reservation of resources in the network. Resource blocks provide a means for recording the bandwidth settings Resource blocks include n n n Maximum reserved bandwidth Maximum traffic burst size Packet length Revised Spring 2006 Rudimentary NMS Software Components 33

Tunnels and LSPs n MPLS-encapsulated packets enter the tunnel, pass across the appropiaye path, and exhibit three important characteristics n n n Forwarding is based on MPLS label rather than IP header Resource usage is fixed, based on those rederved at the time of connection creation The path taken by the traffic is constrained by the path chosen in advance by the user. Revised Spring 2006 Rudimentary NMS Software Components 34

In-Segments and Out-Segments n n In-segments on an MPLS node represent the point of ingress for traffic Out-segments represent the point of egress for traffic Revised Spring 2006 Rudimentary NMS Software Components 35

Cross-Connects n n MPLS node uses the cross-connect settings to decide how to switch traffic between the segments Connection Types n n n Point-to-Point-to-Multipoint-to-Point Revised Spring 2006 Rudimentary NMS Software Components 36

Routing Protocols n MPLS incorporates standard IP routing protocols such as OSPF, IS-IS and BGP 4 Revised Spring 2006 Rudimentary NMS Software Components 37

Signaling Protocols n n LSPs and tunnels can be achieved either manually or via signaling Signaled connections have n n n Resource Reserved Labels Distributed Paths selected by protocols n n RSVP-TE LDP Revised Spring 2006 Rudimentary NMS Software Components 38

Label Operations n n MPLS-labeled traffic is forwarded based on its encapsulated value The operations that can be executed against labels are n n Lookup Swap Pop Push Revised Spring 2006 Rudimentary NMS Software Components 39

MPLS Encapsulation n The MPLS Encapsulation specifies four reserved label values n n 0 -IPv 4 explicit null that signals the receiving node to pop the label and execute an IP lookup 1 -Router alert that indicates to the receiving node to examine the packet more closely (rather than simply forwarding it) 2 -IPv 6 explicit null 3 -Implicit null that signals the receiving node to pop the label and execute an IP lookup Revised Spring 2006 Rudimentary NMS Software Components 40

Qos and Traffic Engineering n LAN Bandwidth can be increased as needed using switches n n Excess bandwidth helps avoid congestion Traffic Engineering is set to become a mandatory element of converged layer 3 enterprise networks. Revised Spring 2006 Rudimentary NMS Software Components 41

Qo. S n There are three approaches that can be adopted for providing different levels of network service n n n Best effort (as provided by the Internet) Fine granularity Qo. S (Integrated Services – Int. Serv) Coarse granularity Qo. S (Differentiated Services – Diff. Serv) Revised Spring 2006 Rudimentary NMS Software Components 42

IP Header Revised Spring 2006 Rudimentary NMS Software Components 43

MPLS and Scalability n n n This table can include millions of rows It is not practical to try to read or write an object of this size using SNMP Unfortunately, it might be necessary if a network is being initially commissioned or rebalanced after adding new hardware Revised Spring 2006 Rudimentary NMS Software Components 44

MPLS and Scalability Revised Spring 2006 Rudimentary NMS Software Components 45

MPLS and Scalability Revised Spring 2006 Rudimentary NMS Software Components 46

Summary n n n Bringing managed data and code together is one of the central foundations of computing and network management Designers of management systems need rarified skills set that matches the range of technologies embedded in NEs and networks Liberal use of standards documents and linked overviews are some important tools for tackling the complexity of system development, managed object derivation, and definition. Networks must increasingly support a growing range of traffic types. (Traffic Engineering and Qo. S handling in Layer 2 and Layer 3 Networks). Revised Spring 2006 Rudimentary NMS Software Components 47