20683: Networking Diagnostics Introduction
Mike Fox
[email protected]
Acknowledgement: based on a presentation initially
developed by Thomas Cosenza
Insert Custom Session QR if Desired.
Agenda
•
Review of Networking basics
•
Configuration
•
Routing
Review: Network Architecture
•
The Base Architecture OSI Model
•
Each Layer provides a different
set of services
•
This Architecture is used for other
protocols as well as TCP/IP
Data Link
Application
Presentation
Session
Transport
Networking
Physical
Data Link
Application
Presentation
Session
Transport
Networking
Physical
TN3270 Server
TN3270E
SSL/TLS
TCP Port 23
IP Address
Ethernet Protocol
OSA Card and Wire
So What is TCP/IP
•
TCP/IP is the
merger of two
protocols,
–
Transmission
Control Protocol
–
Internet Protocol
•
TCP and IP are at
different levels of
the OSI Model
Data Link
Application
Presentation
Session
Transport
Networking
Physical
TCP IPLets take a look at How interfaces work on z/OS
•
There are two main
types of interfaces
–
Real
•
OSA Express
•
MPC
•
XCF
•
Hipersocket
–
Virtual IP address (VIPA)
•
Static
•
Dynamic
•
Distributed
VIPA Address 5.5.5.5/32OSA
OSA
10.5.1.2/28
10.5.1.8/28
7 TN3270e Server VIPA#1 CICS Appl-A VIPA#2 FTP Services VIPA#3 DB2 subsystem VIPA#4
OSA OSA OSA
CICS Appl-B
VIPA#5
Web Services
VIPA#6
IP#10 IP#11 IP#12
Connect to VIPA#1 Connect to CICS-Appl-A.xyz.com My z/OS IP host Resolve CICS-Appl-A.xyz.com
Use IP address VIPA#2
Name server
A VIPA is an IP address that is not
tied to a specific physical interface
and instead represents a higher level concept such as
a host, an application, or a load
balancer.
VIPA#7
Virtual IP address (VIPA)
•
z/OS has 3 types of VIPAs
–
Static
•
Enables recovery from a physical interface failure
–
Dynamic
•
Enables recovery from an IP Stack or LPAR failure
–
Distributed
•
Enables recovery from an IP Stack or LPAR failure
How do I look at my Network on z/OS
•
Netstat command
–
This is a standard command that is available on multiple platforms
•
On z/OS, it can be run from one of three places
–
z/OS Main Console:
D TCPIP,,NETSTAT,<Parms>
•
Note: NETSTAT can be shortened to N
–
TSO: NETSTAT <Parms>
How do I look at my Network on z/OS <cont>
•
Through the next group of slides I will be doing examples from each
•
The Netstat commands for the console can be found in the
IP
System Administrator’s
Commands
–
Chapter 1: Operator commands and system administration
•
DISPLAY TCPIP command
– DISPLAY TCPIP,,NETSTAT subsection
•
Netstat commands for TSO and z/OS UNIX can also be found in
IP System Administrator’s
Commands
.
–
Netstat section of Chapter 3: Monitoring the TCP/IP network.
Agenda
•
Review of Networking Basics
•
Configuration
•
Routing
What are the networking configuration parameters on my z/OS?
•
It is important to figure out the following when looking at z/OS networking
–
What configuration options do I have turned on
–
What are my IP addresses
What are my Configuration Options
•
Understanding this is crucial to figuring out what is going on. These
options will change how your z/OS will react.
–
Console
• D TCPIP,<tcpip stack>,N,CONFIG
–
TSO
• NETSTAT CONFIG
–
z/OS UNIX
Netstat Configuration from console
After doing a D TCPIP,,N,CONFIG
TCP and
UDP Options
Config cont (IP Configuration)
And Much Much more
What About my devices
•
There is a Device command that you can use to find out device
specifics such as Status of the device, MTU size, VLan, BSD routing
parms and more.
–
Console
•
D TCPIP,,N,DEV
(,intfname=Interface name)
– Intfnanme is used to filter to one interface–
TSO
•
TSO NETSTAT DEV
(intfn <interface name>
–
z/OS UNIX
So using it from TSO
What about my IP addresses
•
To see the addresses you have configured you can do a
display of your home list
–
Console
•
D TCPIP,,N,HOME
(,intfname=Interface name)
–
Intfnanme is used to filter to one interface
–
TSO
•
TSO NETSTAT Home
(intfn<interface name>
–
z/OS UNIX
Home display from z/OS UNIX
IPv4 interface
Agenda
•
Review of Networking Basics
•
Configuration
•
Routing
Routing
•
Main issue in Enterprise Shops.
•
To Maintain Network
–
Manipulate Configuration
–
Display information
•
Understanding the types of routes that you can have helps as
well
Types of Routes
•
There are several Types of routes with the following
order of precedence
1.
Implicit Routes
2.
Static Routes
3.
Dynamic Routes
Types or Routes
•
Implicit Route
– This is a Route that is linked to an interface on the stack
•
Static Route
– A Route that is defined to the stack in the TCP/IP Profile. Cannot be replaced by any dynamic route discovery
– “Must use” route
•
Dynamic Route
– Routes found by OMPROUTE using OSPF or RIP.
• It is recommend that you use OSPF due to limitations of Rip
•
Replaceable Static Route
– A route that is defined to the stack in the TCP/IP profile with a parameter that allows it to be replaced if a dynamic route is found to the same destination
So How do I look at my routes
•
With a Netstat Route command you can view the routes on
your system
–
Console
•
D TCPIP,,N,Route
–
TSO
•
TSO NETSTAT Route
–
z/OS UNIX
What are those flags for
The Flags give you
information on the
type of routes these
are and if they are
available for use
What do those Flags mean
•
The following are flags that can be found on a route
display.
• U the route is up
• G the route uses a Gateway (has a non-zero next hop, destination is not directly connected)
• H route destination is a Host Address (the destination is a host, not a network or subnet)
• S Static Route
• O Dynamic OSPF Route
• R Dynamic Rip Route
• Z Replaceable static route
• D Route was created by an ICMP redirect (IPv4) or Router Advertisement (IPv6)
Some other Route displays
Multiple routes to the same destination. Their use is controlled by IPCONFIG
MULTIPATH
Implicit route to a local VIPA interface
Replaceable static route
How do I see what Replaceable static Routes do I have
RSTAT
parameter on
Netstat Route
How to look at OMPROUTE
•
OMPROUTE is the routing daemon on z/OS
•
Some Modify Omproute Commands do a display
–
Note these commands are also available via d tcpip command but this way
saves some typing
•
F <omproute_jobname>,<display command>
is equivalent to
Can I look at my routing using my routing process
Display what
OMPROUTE
knows about a
specific
destination. Note
that the route
being used is a
subnet route…
most specific
match.
Omproute OSPF Neighbors
Different states are not
necessarily an error.
On a LAN, the
Designated Router and
the Backup Designated
Router will be in
neighbor state 128 (full
adjacency). Everyone
else will be 8 (two-way
communication)
OSPF Interface information
This broadcast
interface is not
connected to a
designated router. The
network may just be
coming up and not
have elected one yet,
or there may be a
problem with no DR
configured on this
network
Agenda
•
Review of Networking Basics
•
Configuration
•
Routing
Sysplex
•
At the heart of z/OS is Sysplex Architecture.
•
This technology allows your applications to enjoy high
availability while not having to buy any new hardware on
z/OS
From 10000 ft
Application Layer
WAS
Sysplex Layer
Hardware/OS Layer
IPStack
So How do I see what I have configured on my Sysplex
•
There are Three Types of VIPAS in Sysplex
–
Dynamic Vipa
–
Distributed Vipa
–
Range Vipa
•
Also you have to find out where the backup DVipas are defined
•
Also it is important to know where connections are established in the
Sysplex
Looking at Vipa Dynamics
•
First you want to look at what Vipas are defined on each of
your sysplex systems.
–
Console
•
D TCPIP,,N, VIPADYN
–
TSO
•
TSO NETSTAT VIPADYN
–
z/OS UNIX
Looking at Vipa Configurations
•
The next thing you need to look at when troubleshooting a
Sysplex issue is what are the configurations and where are
the Vipas.
–
Console
•
D TCPIP,,N, VIPADCFG
–
TSO
•
TSO NETSTAT VIPADCFG
–
z/OS Unix
Using VIPADYN to see configuration
• This TCP/IP stack is the primary owner for
197.11.104.190 and is the backup owner for the rest.
• 197.11.104.190 and 197.11.108.190 are currently active here but are not being
distributed.
• This stack is also a VIPA distribution target for 197.11.200.1.
You can also see your VIPA Routes
This shows you the
VIPAROUTE definitions on this host. It shows you which static VIPAs TCP/IP will route to, in order to reach each other host in the sysplex.
For example, if this host needs to distribute sysplex traffic to 199.11.80.104, it will use the IP routing table’s best route to 197.11.104.1, which is assumed to be a static VIPA on that host.
Use VIPACFG to get more information
This stack has VIPA
distribution defined for
DVIPA 197.11.201.1.
This display shows how it
traffic to that DVIPA is
distributed to the other
hosts in the sysplex, for
different ports. (note that
in this example, each
port is distributed to all
hosts in the sysplex)
What if it is a back up??
This host is the
backup for DVIPA
197.11.108.190,
with a rank of 50
Looking at Vipa Connections
•
Once you establish where your Dynamic Vipas are you need
to find out who is connecting to them.
–
Console
•
D TCPIP,,N, VCRT
–
TSO
•
TSO NETSTAT VCRT
–
z/OS UNIX
•
onetstat –V
Who is connecting to a Dynamic Vipa address
Translation: The
connection from origin
197.11.105.1 port 30930
to DIPVA 197.11.201.1
port 4159 is being
serviced by the sysplex
host with Dynamic XCF
address 199.11.80.104
Looking at where Distributed Vipa Connections will go
•
You also may need to figure out where new connections will
go to.
•
So you
–
Console
•
D TCPIP,,N, VDPT
–
TSO
•
TSO NETSTAT VDPT
–
Unix
•
onetstat –O
Where do Distributed connections Route to
• TOTALCONN is the number of connections that have been
forwarded to this target. This value wraps.
• RDY is the number of applications ready to receive connections on the distribution target. • WLM is the WLM weight
for the listener. Higher numbers indicate more capacity
• TSR is the Target
Server Responsiveness for the target server. 100 indicates that the server is successfully accepting all
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